// ~~ Be name khoda ~~ //
#include <bits/stdc++.h>
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2")
using namespace std;
typedef long long ll;
#define all(x) x.begin(), x.end()
#define fi first
#define se second
#define pb push_back
const int maxn5 = 1e5 + 10;
const int maxnt = 4e5 + 10;
const ll inf = 2e18;
struct segment_tree{
ll val[maxn5], lazy[maxnt];
pair <ll, int> mx[maxnt];
inline void build(int l, int r, int v){
if(r - l == 1){
mx[v] = {val[l], l};
return;
}
int mid = (l + r) >> 1;
build(l, mid, v * 2);
build(mid, r, v * 2 + 1);
mx[v] = max(mx[v * 2], mx[v * 2 + 1]);
}
inline void add(int l, int r, int lq, int rq, ll valu, int v){
if(rq <= l || r <= lq)
return;
if(lq <= l && r <= rq){
lazy[v] += valu;
mx[v].fi += valu;
return;
}
int mid = (l + r) >> 1;
add(l, mid, lq, rq, valu, v * 2);
add(mid, r, lq, rq, valu, v * 2 + 1);
mx[v] = max(mx[v * 2], mx[v * 2 + 1]);
mx[v].fi += lazy[v];
}
inline void update(int l, int r, int id, ll valu, int v){
if(r - l == 1){
val[l] = valu;
mx[v] = {valu, l};
//cout << "update for " << l << ' ' << valu << endl;
return;
}
int mid = (l + r) >> 1;
if(id < mid)
update(l, mid, id, valu - lazy[v], v * 2);
else
update(mid, r, id, valu - lazy[v], v * 2 + 1);
mx[v] = max(mx[v * 2], mx[v * 2 + 1]);
}
inline pair<ll, int> get_max(int l, int r, int lq, int rq, int v){
if(rq <= l || r <= lq)
return {-inf, 0};
if(lq <= l && r <= rq)
return mx[v];
int mid = (l + r) >> 1;
auto ans = max(get_max(l, mid, lq, rq, v * 2), get_max(mid, r, lq, rq, v * 2 + 1));
//cout << "hey see this " << l << ' ' << r << ' ' << lq << ' ' << rq << ' ' << ans.fi << ' ' << ans.se << ' ' << lazy[v] << endl;
return {ans.fi + lazy[v], ans.se};
}
} fut_seg, hld_seg;
int ti = -1, st[maxn5], ft[maxn5], pos = 0, n;
int id[maxn5], big[maxn5], sz[maxn5], top[maxn5], ver[maxn5];
int h[maxn5], f[maxn5], a[maxn5], b[maxn5], retuid[maxn5];
ll hw[maxn5], mxw[maxn5], paredge[maxn5], c[maxn5];
vector <pair<int, ll>> adj[maxn5];
inline void dfs_det(int v, int par){
sz[v] = 1;
big[v] = -1;
st[v] = ++ti;
ver[ti] = v;
mxw[v] = 0;
for(auto [u, c] : adj[v]) if(u != par){
h[u] = h[v] + 1;
hw[u] = hw[v] + c;
paredge[u] = c;
dfs_det(u, v);
sz[v] += sz[u];
mxw[v] = max(mxw[v], mxw[u] + c);
if(big[v] == -1 || sz[big[v]] <= sz[u])
big[v] = u;
}
ft[v] = ti;
return;
}
inline void dfs_hld(int v, int par){
id[v] = pos++;
if(big[v] != -1){
top[big[v]] = top[v];
f[big[v]] = f[v];
dfs_hld(big[v], v);
}
ll val = 0;
for(auto [u, c] : adj[v]) if(u != big[v] && u != par){
f[u] = v;
top[u] = u;
val = max(val, (mxw[u] + c));
dfs_hld(u, v);
}
//cout << "ok " << v << ' ' << id[v] << ' ' << val << ' ' << hw[v] << endl;
hld_seg.val[id[v]] = val - hw[v];
retuid[v] = pos;
return;
}
inline void update(int v, int u){
if(v == -1)
return;
if(u != big[v]){
//cout << "in case of " << v << ' ' << u << ' ' << st[v] << ' ' << ft[v] << ' ' << st[u] << ' ' << ft[u] << ' ' << st[big[v]] << ' '<< ft[big[v]] << endl;
ll val = fut_seg.get_max(0, n, st[v], st[big[v]], 1).fi;
//cout << "a " << val << endl;
val = max(val, fut_seg.get_max(0, n, ft[big[v]] + 1, ft[v] + 1, 1).fi);
hld_seg.update(0, n, id[v], val - 2 * fut_seg.get_max(0, n, st[v], st[v] + 1, 1).fi, 1);
//cout << "with final value " << val << ' ' << id[v] << ' ' << big[v] << ' ' << fut_seg.get_max(0, n, st[v], st[v] + 1, 1).fi << endl;
//cout << "done " << endl;
}
update(f[v], top[v]);
}
inline ll get(int v){
//cout << "all about getting " << v << ' ' << f[v] << ' ' << top[v] << endl;
auto tmp = hld_seg.get_max(0, n, id[top[v]], id[v], 1);
ll res = tmp.fi;
//cout << tmp.se << endl;
//cout << res << endl;
if(f[v] == -1)
return res;
res = max(res, get(f[v]));
int u = top[v];
int z = f[v];
ll ezafe = fut_seg.get_max(0, n, st[z], st[z] + 1, 1).fi;
ezafe *= 2;
res = max(res, fut_seg.get_max(0, n, st[z], st[u], 1).fi - ezafe);
res = max(res, fut_seg.get_max(0, n, ft[u] + 1, ft[z] + 1, 1).fi - ezafe);
//cout << "returning " << res << endl;
return res;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
ll w;
int q; cin >> n >> q >> w;
for(int i = 0; i < n - 1; i++){
cin >> a[i] >> b[i] >> c[i];
a[i]--; b[i]--;
adj[a[i]].pb({b[i], c[i]});
adj[b[i]].pb({a[i], c[i]});
}
f[0] = -1;
top[0] = 0;
dfs_det(0, -1);
dfs_hld(0, -1);
for(int i = 0; i < n; i++)
fut_seg.val[st[i]] = hw[i];
fut_seg.build(0, n, 1);
hld_seg.build(0, n, 1);
//cout << "avale kar " << fut_seg.get_max(0, n, st[9], st[big[9]], 1).fi << endl;
ll last = 0;
for(int i = 0; i < q; i++){
ll d, e; cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
//cout << "________________query " << d << ' ' << e << endl;
if(st[a[d]] > st[b[d]])
swap(a[d], b[d]);
// a pedar hast
fut_seg.add(0, n, st[b[d]], ft[b[d]] + 1, e - c[d], 1);
//cout << "befor update " << endl;
//cout << "idea of " << st[b[d]] << ' ' << ft[b[d]] << ' ' << b[d] << ' ' << e- c[d] << endl;
//cout << "max is " << fut_seg.get_max(0, n, st[5], ft[5] + 1, 1).fi << endl;
update(a[d], b[d]);
hld_seg.add(0, n, id[b[d]], retuid[b[d]] + 1, -e + c[d], 1);
auto tmp = fut_seg.mx[1];
int v = ver[tmp.se];
//cout << "found " << v << ' ' << tmp.fi << endl;
last = tmp.fi + get(v);
//cout << "oh! " << last << endl;
last = max(last, tmp.fi);
c[d] = e;
cout << last << '\n';
}
}
/*
10 1 10000
1 9 1241
5 6 1630
10 5 1630
2 6 853
10 1 511
5 3 760
8 3 1076
4 10 1483
7 10 40
8 2051
5 6294
5 4168
7 1861
0 5244
6 5156
3 3001
8 5267
5 3102
8 3623
*/
