#include <bits/stdc++.h>
/*
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")
*/
using namespace std;
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
*/
#define F first
#define S second
#define pb push_back
#define FIO freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout)
#define md(a) (a%mod+mod)%mod
#define all(a) a.begin(), a.end()
#define MP make_pair
#define lc id<<1
#define rc lc|1
#define mid (l+r)/2
#define kill(a) cout << a << "\n", exit(0)
typedef pair<int,int> pii;
typedef pair<long long ,long long> pll;
typedef long long ll;
typedef long double ld;
typedef vector<vector<ll>> matrix;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll const maxn=1e5+10, mod=1e9+7, INF=1e18, LOG=45, sq=65;
ll poww(ll a, ll b, ll mod) {
if (b == 0) return 1;
return 1 * poww(1 * a * a % mod, b / 2, mod) * ((b % 2 == 1) ? a : 1) % mod;
}
ll n, q, w, W[maxn], mx, dis[maxn], dp[maxn];
vector<pll> g[maxn];
void DFS(ll v, ll p=0)
{
vector<pll> vec;
for(auto [u, id]:g[v])
{
if(u!=p)
{
DFS(u, v);
vec.pb({dp[u], id});
}
}
for(auto [i, id]:vec)
{
dp[v]=max(dp[v], i+W[id]);
}
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n>>q>>w;
for(ll i=1;i<n;i++)
{
ll v, u, w;
cin>>v>>u>>w;
g[v].pb({u, i});
g[u].pb({v, i});
W[i]=w;
}
ll last=0;
while(q--)
{
ll d, e;
cin>>d>>e;
d=(d+last)%(n-1);
e=(e+last)%w;
W[d+1]=e;
fill(dp, dp+n+1, 0);
DFS(1);
ll mx=-INF, mx2=-INF;
for(auto [u, id]:g[1])
{
if(dp[u]+W[id]>mx)
{
mx=dp[u]+W[id];
mx2=mx;
}
else if(dp[u]+W[id]>mx2)
{
mx2=dp[u]+W[id];
}
}
if(g[1].size()==1)
{
cout<<dp[1]<<"\n";
last=dp[1];
}
else{
cout<<mx+mx2<<"\n";
last=mx+mx2;
}
}
return 0;
}
