#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define Mp make_pair
#define sep ' '
#define endl '\n'
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define kill(res) cout << res << '\n', exit(0);
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);
#define lid (id*2)
#define rid (id*2+1)
#define mid ((l+r)/2)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 1e5 + 50;
const ll inf = -1e18;
ll n, q, W, w[N], down[N], st[N], ft[N];
vector<int> vec;
vector<pii> adj[N];
void dfs(int v, int p = 0){
st[v] = vec.size(); vec.pb(v);
for(auto [u, i]: adj[v]){
if(u == p) continue;
down[i] = u; dfs(u, v);
vec.pb(v);
}
ft[v] = vec.size();
}
struct dt{
ll mx, mn, lft, rit, dim;
dt(ll a = 0, ll b = 0, ll c = 0, ll d = 0, ll e = 0){
mx = a; mn = b; lft = c; rit = d; dim = e;
}
dt merg(dt x){
dt out;
out.mx = max(mx, x.mx);
out.mn = min(mn, x.mn);
out.lft = max({lft, x.lft, mx - 2 * x.mn});
out.rit = max({rit, x.rit, x.mx - 2 * mn});
out.dim = max({dim, x.dim, lft + x.mx, mx + x.rit});
return out;
}
};
dt seg[N*8]; ll lz[N*8];
void quex(int id, ll x){
lz[id] += x;
seg[id].mx += x;
seg[id].mn += x;
seg[id].lft -= x;
seg[id].rit -= x;
}
void relax(int id){
quex(lid, lz[id]);
quex(rid, lz[id]);
lz[id] = 0;
}
void upd(int ql, int qr, ll x, int l = 0, int r = vec.size(), int id = 1){
if(ql <= l && r <= qr){
quex(id, x); return;
}
if(qr <= l || r <= ql) return;
relax(id);
upd(ql, qr, x, l, mid, lid);
upd(ql, qr, x, mid, r, rid);
seg[id] = seg[lid].merg(seg[rid]);
}
dt get(int ql = 0, int qr = vec.size(), int l = 0, int r = vec.size(), int id = 1){
if(ql <= l && r <= qr) return seg[id];
if(qr <= l || r <= ql) return dt(-inf, inf, -inf, -inf, -inf);
relax(id);
return (get(ql, qr, l, mid, lid)).merg(get(ql, qr, mid, r, rid));
}
int main(){
fast_io;
cin >> n >> q >> W;
int u, v;
for(int i = 0; i < n-1; i++){
cin >> u >> v >> w[i];
adj[u].pb({v, i});
adj[v].pb({u, i});
}
dfs(1);
for(int i = 0; i < n-1; i++) upd(st[down[i]], ft[down[i]], w[i]);
ll last = 0;
while(q--){
ll dj, djp, ej, ejp;
cin >> dj >> ej;
djp = (dj + last) % (n-1);
ejp = (ej + last) % W;
upd(st[down[djp]], ft[down[djp]], ejp - w[djp]); w[djp] = ejp;
last = get().dim;
cout << last << endl;
}
}
