#include <bits/stdc++.h>
#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())
using namespace std;
template<typename U, typename V> bool maxi(U &a, V b) {
if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
if (a > b) { a = b; return 1; } return 0;
}
const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;
void prepare(); void main_code();
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
const bool MULTITEST = 0; prepare();
int num_test = 1; if (MULTITEST) cin >> num_test;
while (num_test--) { main_code(); }
}
void prepare() {};
int n, q;
long long w;
struct edge {
int u, v;
long long w;
edge () {};
edge (int _u, int _v, long long _w) {
u = _u, v = _v, w = _w;
}
int get(int x) {
return x ^ u ^ v;
}
bool operator < (const edge & other) {
return w < other.w;
}
} e[N];
vector<int> g[N];
int par[N];
long long d[N];
int s[N], tin[N], tout[N], cnt = 0;
void euler(int u, int p) {
s[u] = 1;
tin[u] = ++cnt;
for(int id : g[u]) {
int v = e[id].get(u);
if (v != p) {
par[v] = u;
d[v] = d[u] + e[id].w;
euler(v, u);
s[u] += s[v];
}
}
tout[u] = ++cnt;
}
int cc = 0, ch[N], hd[N], pos[N], nxt[N], base[N];
void hld(int u, int p) {
pos[u] = ++cnt;
base[cnt] = u;
ch[u] = cc;
if (hd[cc] == 0) hd[cc] = u;
int mx = -1;
for(int id : g[u]) {
int v = e[id].get(u);
if (v != p) {
if (mx == -1 or s[v] > s[mx])
mx = v;
}
}
if (mx == -1) return ;
nxt[u] = mx;
hld(mx, u);
// cerr << u << ' ' << mx << nl;
for(int id : g[u]) {
int v = e[id].get(u);
if (v != p and v != mx) {
++cc;
hld(v, u);
}
}
}
namespace IT {
int arr[2 * N];
struct segment_tree {
int n;
vector<long long> t, lz;
segment_tree () {};
segment_tree (int _n) {
n = _n;
t.resize(4 * n + 7);
lz.resize(4 * n + 7);
}
void build(int id, int l, int r) {
if (l == r) {
t[id] = d[arr[l]];
return ;
}
int m = (l + r) >> 1;
build(id << 1, l, m);
build(id << 1 | 1, m + 1, r);
t[id] = max(t[id << 1], t[id << 1 | 1]);
}
void push(int id) {
long long &v = lz[id];
t[id << 1] += v;
t[id << 1 | 1] += v;
lz[id << 1] += v;
lz[id << 1 | 1] += v;
v = 0;
}
void update(int id, int l, int r, int u, int v, long long val) {
if (l > v or r < u) return ;
if (l >= u and r <= v) {
t[id] += val;
lz[id] += val;
return ;
}
if (lz[id] != 0) push(id);
int m = (l + r) >> 1;
update(id << 1, l, m, u, v, val);
update(id << 1 | 1, m + 1, r, u, v, val);
t[id] = max(t[id << 1], t[id << 1 | 1]);
}
long long getMax(int id, int l, int r, int u, int v) {
if (l > v or r < u)
return 0;
if (l >= u and r <= v)
return t[id];
if (lz[id] != 0) push(id);
int m = (l + r) >> 1;
return max(getMax(id << 1, l, m, u, v),
getMax(id << 1 | 1, m + 1, r, u, v));
}
long long get(int id, int l, int r, int p) {
if (l == r) return t[id];
if (lz[id] != 0) push(id);
int m = (l + r) >> 1;
return (p <= m ? get(id << 1, l, m, p) :
get(id << 1 | 1, m + 1, r, p));
}
long long get(int x) {
return get(1, 1, n, x);
}
int fx(int id, int l, int r) {
if (l == r) return arr[l];
if (lz[id] != 0) push(id);
int m = (l + r) >> 1;
if (t[id << 1] >= t[id << 1 | 1])
return fx(id << 1, l, m);
return fx(id << 1 | 1, m + 1, r);
}
};
segment_tree st;
void init() {
st = segment_tree(2 * n);
for(int i = 1; i <= n; ++i) {
arr[tin[i]] = arr[tout[i]] = i;
}
// FOR(i, 1, n) cout << d[i] << ' '; cout << nl;
// FOR(i, 1, 2 * n) cout << arr[i] << ' '; cout << nl;
st.build(1, 1, 2 * n);
}
long long getP(int t) {
return st.get(1, 1, 2 * n, tin[t]);
}
long long get(int u, int t) {
if (t == -1) {
return st.getMax(1, 1, 2 * n, tin[u], tout[u]) - 2LL * st.get(tin[u]);
}
long long px = -2LL * st.get(tin[u]);
long long r = 0;
if (tin[u] != tin[t]) {
r = max(r, st.getMax(1, 1, 2 * n, tin[u], tin[t] - 1));
}
if (tout[t] != tout[u]) {
r = max(r, st.getMax(1, 1, 2 * n, tout[t] + 1, tout[u]));
}
return px + r;
}
void update(int l, int r, long long val) {
st.update(1, 1, 2 * n, l, r, val);
}
int fx() {
return st.fx(1, 1, 2 * n);
}
};
struct segment_tree {
// handle point update / get max
// index theo base
int n;
vector<long long> t, lz;
void init (int _n) {
n = _n;
t.resize(4 * n + 7);
lz.resize(4 * n + 7);
}
void push(int id) {
long long &v = lz[id];
t[id << 1] += v;
t[id << 1 | 1] += v;
lz[id << 1] += v;
lz[id << 1 | 1] += v;
v = 0;
}
const long long INF = -(long long)1e17;
void update(int id, int l, int r, int p, long long val) {
if (l == r) {
t[id] = val;
return ;
}
if (lz[id]) push(id);
int m = (l + r) >> 1;
if (p <= m)
update(id << 1, l, m, p, val);
else
update(id << 1 | 1, m + 1, r, p, val);
t[id] = max(t[id << 1], t[id << 1 | 1]);
}
void update(int p, long long val) {
update(1, 1, n, p, val);
}
void update(int id, int l, int r, int u, int v, long long val) {
if (l > v or r < u) return ;
if (l >= u and r <= v) {
t[id] += val;
lz[id] += val;
return ;
}
if (lz[id]) push(id);
int m = (l + r) >> 1;
update(id << 1, l, m, u, v, val);
update(id << 1 | 1, m + 1, r, u, v, val);
t[id] = max(t[id << 1], t[id << 1 | 1]);
}
void update(int l, int r, long long val) {
update(1, 1, n, l, r, val);
}
long long get(int id, int l, int r, int u, int v) {
if (l > v or r < u) return INF;
if (l >= u and r <= v) return t[id];
if (lz[id]) push(id);
int m = (l + r) >> 1;
return max(get(id << 1, l, m, u, v),
get(id << 1 | 1, m + 1, r, u, v));
}
long long get(int l, int r) {
return get(1, 1, n, l, r);
}
} T;
int mxx[N];
void dfs2(int u, int p) {
mxx[u] = pos[u];
for(int id : g[u]) {
int v = e[id].get(u);
if (v != p) {
dfs2(v,u);
mxx[u]=max(mxx[u], mxx[v]);
}
}
}
void main_code() {
cin >> n >> q >> w;
for(int i = 1; i < n; ++i) {
int u, v; long long c;
cin >> u >> v >> c;
e[i] = edge(u, v, c);
g[u].push_back(i);
g[v].push_back(i);
}
euler(1, 0);
cnt = 0;
FOR(i, 1, n) nxt[i] = -1;
hld(1, 0);
dfs2(1,0);
IT::init();
T.init(n);
for(int i = 1; i <= n; ++i) {
T.update(pos[i], IT::get(i, nxt[i]));
}
long long last = 0;
FOR(i, 1, n - 1) {
if (d[e[i].u] > d[e[i].v])
swap(e[i].u, e[i].v);
}
// FOR(i, 1, n) cout << ch[i] << ' '; cout << nl;
// FOR(i, 0, cc) cout << hd[i] << ' '; cout << nl;
// return ;
while (q--) {
long long dj, ej;
cin >> dj >> ej;
dj = (dj + last) % (n - 1);
ej = (ej + last) % w;
++dj; // edge thu dj
long long vx = ej - e[dj].w;
e[dj].w = ej;
// cerr << "dj: " << dj << nl;
// cerr << "vx: " << vx << nl;
// update lai da
int u = e[dj].u, v = e[dj].v;
IT::update(tin[v], tout[v], vx);
// if (ch[u] != ch[v]) {
// T.update(pos[v], IT::get(v, nxt[v]));
// }
T.update(pos[v], mxx[v], -vx);
for(int cur = v; ;) {
cur = hd[ch[cur]];
if (cur == 1) break ;
int p = par[cur];
T.update(pos[p], IT::get(p, nxt[p]));
cur = p;
}
int k = IT::fx();
// cerr << k << nl;
//get cai d cua no luon
long long dk = IT::getP(k);
// cerr << "dk: " << dk << nl;
long long ans = 0;
for(int cur = k; ;) {
int a = hd[ch[cur]];
if (a != cur) {
ans = max(ans, T.get(pos[a], pos[par[cur]]) + dk);
}
if (a == 1) break ;
int p = par[a];
ans = max(ans, IT::get(p, a) + dk);
cur = p;
}
cout << ans << nl;
last = ans;
}
}
/* Let the river flows naturally */
