///*** Sown_Vipro ***///
/// ->TUYEN QUOC GIA<- ///
#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define all(a) a.begin(), a.end()
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
#define out(name) if(fopen(name, "w")) freopen(name, "w", stdout);
#define szz(s) int(s.size())
const int N = 2e5 + 5, MAX = 1e6, MOD = 1e9 + 7;
const long long oo = 1e18 + 5;
int n, q, m, TIME;
long long W, lz[4 * N], res, d[N];
int in[N], out[N], ver[N], h[N];
vector<pi> e[N];
struct ed{
int u, v;
long long w;
} edge[N];
void euler(int u, int p){
in[u] = ++m;
out[u] = m;
ver[m] = u;
for(auto [v, w] : e[u]){
if(v == p) continue;
h[v] = h[u] + 1;
d[v] = d[u] + w;
euler(v, u);
}
if(p != 0){
out[p] = ++m;
ver[m] = p;
}
}
struct node{
long long du = oo, dv = -oo, duw = -oo, dwv = -oo, duwv = 0;
} st[4 * N];
void down(int id){
st[2 * id].du += lz[id];
st[2 * id].dv += lz[id];
st[2 * id].duw -= lz[id];
st[2 * id].dwv -= lz[id];
lz[2 * id] += lz[id];
st[2 * id + 1].du += lz[id];
st[2 * id + 1].dv += lz[id];
st[2 * id + 1].duw -= lz[id];
st[2 * id + 1].dwv -= lz[id];
lz[2 * id + 1] += lz[id];
lz[id] = 0;
}
node Merge(node A, node B, int l, int r){
node res;
res.du = min(A.du, B.du);
res.dv = max(A.dv, B.dv);
res.duw = max({A.duw, B.duw, A.dv - 2 * B.du});
res.dwv = max({A.dwv, B.dwv, B.dv - 2 * A.du});
res.duwv = max({A.duwv, B.duwv, A.duw + B.dv, A.dv + B.dwv});
// cout << l << " " << r << " " << A.duw << " " << B.dv << " " << A.dv << " " << B.dwv << "\n";
return res;
}
void build(int id, int l, int r){
if(l == r){
st[id].du = st[id].dv = d[ver[l]];
st[id].duw = st[id].dwv = -d[ver[l]];
return;
}
int m = (l + r) / 2;
build(2 * id, l, m);
build(2 * id + 1, m + 1, r);
st[id] = Merge(st[2 * id], st[2 * id + 1], l, r);
// cout << l << " " << r << " " << id << " " << st[id].dv << "\n";
}
void update(int id, int l, int r, int u, int v, int x){
if(l > v || r < u) return;
if(u <= l && r <= v){
st[id].du += x;
st[id].dv += x;
st[id].duw -= x;
st[id].dwv -= x;
lz[id] += x;
return;
}
down(id);
int m = (l + r) / 2;
update(2 * id, l, m, u, v, x);
update(2 * id + 1, m + 1, r, u, v, x);
st[id] = Merge(st[2 * id], st[2 * id + 1], l, r);
// cout << l << " " << r << " " << id << " " << st[id].dv << "\n";
}
void solve(){
cin >> n >> q >> W;
FOR(i, 1, n - 1){
int u, v, w; cin >> u >> v >> w;
e[u].pb({v, w});
e[v].pb({u, w});
edge[i] = {u, v, w};
}
euler(1, 0);
build(1, 1, m);
// FOR(i, 1, m) cout << ver[i] << " ";
// cout << "\n";
// cout << st[1].dv;
while(q--){
int d; long long e;
cin >> d >> e;
d = (d + res) % (n - 1) + 1;
e = (e + res) % W;
// cout << d << " " << e << " ";
int u = edge[d].u, v = edge[d].v, w = edge[d].w;
if(h[u] > h[v]) swap(u, v);
// cout << u << " " << v << "\n";
update(1, 1, m, in[v], out[v], e - w);
res = st[1].duwv;
cout << res << "\n";
edge[d].w = e;
// break;
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
// inp("in.txt");
// out("out.txt");
int t = 1;
// cin >> t;
while(t--){
solve();
}
}
