#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
#define FOR(i,l,r,d) for(int i=(l);i<=(r);i+=(d))
#define szof(x) ((int)(x).size())
#define vi vector<int>
#define pii pair<int,int>
#define F first
#define S second
#define pb push_back
#define eb emplace_back
#define mkp make_pair
#define Data_Structures
#ifdef Data_Structures
#define V st[cidx]
#define LC st[cidx*2]
#define RC st[cidx*2+1]
#define lsb(x) ((x)&(-(x)))
#endif
const int INF = 2147483647;
const int LNF = INF*INF;
const int MOD = 1000000007;
const int mod = 998244353;
const double eps = 1e-12;
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
const int MAX = 100010;
/// vertices: 1-indexed
/// edges: 0-indexed
int n, q, W;
vector<vi> edge[MAX]; /// to, w, idx
int el[MAX], er[MAX];
int eval[MAX];
int qd[MAX], qe[MAX];
int res[MAX];
int arr[2*MAX];
int from[MAX], to[MAX];
int stamp = 0;
void dfs(int v, int pv, int dep){
from[v] = to[v] = stamp;
arr[stamp] = dep;
stamp++;
for(vi e : edge[v]){
int i = e[0];
if(i==pv) continue;
dfs(i, v, dep + e[1]);
el[e[2]] = from[i];
er[e[2]] = to[i];
to[v] = stamp;
arr[stamp] = dep;
stamp++;
}
}
struct Node{
int sl, sr;
int Max, Min, ul, lv, ulv;
int tag;
};
Node st[8*MAX];
void build(int cidx, int cl, int cr){
V.sl = cl;
V.sr = cr;
V.Max = 0;
V.Min = 0;
V.ul = 0;
V.lv = 0;
V.ulv = 0;
if(cl < cr){
int mid = (cl + cr) / 2;
build(cidx*2, cl, mid);
build(cidx*2+1, mid+1, cr);
}
}
void push_tag(int cidx){
V.Max += V.tag;
V.Min += V.tag;
V.ul -= V.tag;
V.lv -= V.tag;
if(V.sl < V.sr){
LC.tag += V.tag;
RC.tag += V.tag;
}
V.tag = 0;
}
void pull(int cidx){
push_tag(cidx);
if(V.sl < V.sr){
push_tag(cidx*2);
push_tag(cidx*2+1);
V.Max = max(LC.Max, RC.Max);
V.Min = min(LC.Min, RC.Min);
V.ul = max({LC.ul, RC.ul, LC.Max - 2*RC.Min});
V.lv = max({LC.lv, RC.lv, -2*LC.Min + RC.Max});
V.ulv = max({LC.ulv, RC.ulv, LC.ul + RC.Max, LC.Max + RC.lv});
}
}
void modify(int cidx, int ml, int mr, int val){
if(mr<V.sl or V.sr<ml){
return;
}
if(ml<=V.sl and V.sr<=mr){
V.tag += val;
return;
}
push_tag(cidx);
modify(cidx*2, ml, mr, val);
modify(cidx*2+1, ml, mr, val);
pull(cidx);
}
int query(){
return st[1].ulv;
}
void debug(int cidx){
if(cidx==1){
cerr<<"debug : ";
}
push_tag(cidx);
pull(cidx);
if(V.sl < V.sr){
debug(cidx*2);
debug(cidx*2+1);
}
else{
cerr<<V.Max<<" ";
}
if(cidx==1){
cerr<<endl;
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>q>>W;
FOR(i, 0, n-2, 1){
int u, v, w;
cin>>u>>v>>w;
edge[u].pb({v, w, i});
edge[v].pb({u, w, i});
eval[i] = w;
}
dfs(1, -1, 0);
build(1, 0, 2*n-2);
FOR(i, 0, n-2, 1){
modify(1, el[i], er[i], eval[i]);
}
//debug(1);
FOR(i, 0, q-1, 1){
cin>>qd[i]>>qe[i];
int last = 0;
if(i > 0) last = res[i-1];
qd[i] = (qd[i] + last) % (n-1);
qe[i] = (qe[i] + last) % W;
int delta = qe[i] - eval[qd[i]];
eval[qd[i]] = qe[i];
modify(1, el[qd[i]], er[qd[i]], delta);
res[i] = query();
//debug(1);
}
FOR(i, 0, q-1, 1){
cout<<res[i]<<'\n';
}
return 0;
}
