#include <bits/stdc++.h> using namespace std; #define int long long #define endl '\n' const int M = 1e5 + 1; struct node { int x, l, i; }; int subt[M], st[M], en[M], par[M], nx[M], id[M], cnt[M], ind[M], rev[M], t, t1, n; node seg[M*2]; vector<pair<int,int>> nei[M],nei1[M]; vector<node> seg1[M]; void push(int v,int lc,int rc) { seg[lc].x+=seg[v].l, seg[lc].l+=seg[v].l; seg[rc].x+=seg[v].l, seg[rc].l+=seg[v].l; seg[v].l=0; } node merge(node a, node b) { if (b.x>a.x) a=b; a.l=0; return a; } void modify(int l,int r,int x,int v=0,int s=0,int e=n) { if (l>=e or r<=s) return; if (l<=s && e<=r) { if (s+1==e) seg[v].i=s; seg[v].x+=x, seg[v].l+=x; return; } int mid=(s+e)/2, lc=v+1, rc=v+(mid-s)*2; push(v,lc,rc); modify(l,r,x,lc,s,mid); modify(l,r,x,rc,mid,e); seg[v]=merge(seg[lc],seg[rc]); } node get(int l,int r,int v=0,int s=0,int e=n) { if (l>=e or r<=s) return {0,0,0}; if (l<=s && e<=r) return seg[v]; int mid=(s+e)/2, lc=v+1, rc=v+(mid-s)*2; push(v,lc,rc); return merge(get(l,r,lc,s,mid),get(l,r,rc,mid,e)); } void push1(int v,int lc,int rc,int i) { seg1[i][lc].x+=seg1[i][v].l, seg1[i][lc].l+=seg1[i][v].l; seg1[i][rc].x+=seg1[i][v].l, seg1[i][rc].l+=seg1[i][v].l; seg1[i][v].l=0; } void mod(int l,int r,int x,int i,int v,int s,int e) { if (l>=e or r<=s) return; if (l<=s && e<=r) { seg1[i][v].x+=x, seg1[i][v].l+=x; return; } int mid=(s+e)/2, lc=v+1, rc=v+(mid-s)*2; push1(v,lc,rc,i); mod(l,r,x,i,lc,s,mid); mod(l,r,x,i,rc,mid,e); seg1[i][v]=merge(seg1[i][lc],seg1[i][rc]); } int get1(int l,int r,int i,int v,int s,int e) { if (l>=e or r<=s) return -M*3; if (l<=s && e<=r) return seg1[i][v].x; int mid=(s+e)/2, lc=v+1, rc=v+(mid-s)*2; push1(v,lc,rc,i); return max(get1(l,r,i,lc,s,mid),get1(l,r,i,rc,mid,e)); } void dfs(int u) { subt[u]=1; for (int i=0;i+1<nei[u].size();i++) if (nei[u][i].first==par[u]) swap(nei[u][i],nei[u][i+1]); if (par[u]) nei[u].pop_back(); for (auto [i,w]:nei[u]) if (i!=par[u]) par[i]=u, dfs(i), subt[u]+=subt[i]; for (int i=(int)nei[u].size()-1;i>0;i--) if (subt[nei[u][i].first]>subt[nei[u][i-1].first]) swap(nei[u][i], nei[u][i-1]); } void doit(int u) { if (nei[u].empty()) return; nx[nei[u][0].first]=nx[u], id[nei[u][0].first]=id[u], ind[nei[u][0].first]=ind[u]+1, cnt[id[u]]++; for (auto [i,w]:nei[u]) { if (i!=nei[u][0].first) nx[i]=i, id[i]=t1++, ind[i]=0, cnt[id[i]]++; doit(i); } } void et(int u,int val=0) { st[u]=t++, rev[st[u]]=u; modify(st[u],st[u]+1,val); for (auto [i,w]:nei[u]) et(i,val+w), nei1[u].push_back({en[i],i}); en[u]=t; } signed main() { ios::sync_with_stdio(0); cin.tie(NULL), cout.tie(NULL); int q,W; cin>>n>>q>>W; int u[n], v[n], w[n]; for (int i=0;i<n-1;i++) { cin>>u[i]>>v[i]>>w[i]; nei[u[i]].push_back({v[i],w[i]}); nei[v[i]].push_back({u[i],w[i]}); } dfs(1); et(1); nx[1]=1, id[1]=t1++, cnt[0]++, ind[1]=0; doit(1); for (int i=0;i<t1;i++) seg1[i]=vector<node>(cnt[i]*2); for (int i=1;i<=n;i++) { int x=get(st[nx[i]],st[nx[i]]+1).x; mod(ind[i],ind[i]+1,(nei[i].size()?get(en[nei[i][0].first],en[i]).x-2*get(st[i],st[i]+1).x+x:0),id[i],0,0,cnt[id[i]]); } for (int i=0;i<n-1;i++) if (st[v[i]]>st[u[i]]) swap(u[i],v[i]); int ls=0; while (q--) { int d,e; cin>>d>>e; d=(d+ls)%(n-1), e=(e+ls)%W; modify(st[u[d]],en[u[d]],e-w[d]); int up=u[d]; if (nx[up]!=up) mod(ind[up],cnt[id[up]],w[d]-e,id[up],0,0,cnt[id[up]]); while (par[up]) { if (up==nx[up]) { int o=get1(ind[par[up]],ind[par[up]]+1,id[par[up]],0,0,cnt[id[par[up]]]); mod(ind[par[up]],ind[par[up]]+1,get(en[nei[par[up]][0].first],en[par[up]]).x-2*get(st[par[up]],st[par[up]]+1).x+get(st[nx[par[up]]],st[nx[par[up]]]+1).x-o,id[par[up]],0,0,cnt[id[par[up]]]),up=par[up]; } else up=nx[up]; } node nd=get(0,n); int val=nd.x, mx=0,u=rev[nd.i]; while (par[u]) { if (nei[par[u]][0].first==u) mx=max(mx,get1(0,ind[par[u]]+1,id[par[u]],0,0,cnt[id[par[u]]])-get(st[nx[u]],st[nx[u]]+1).x), u=nx[u]; else { int x=lower_bound(nei1[par[u]].begin(),nei1[par[u]].end(),make_pair(en[u],0ll))-begin(nei1[par[u]]); mx=max(mx,merge(get(st[par[u]],st[nei[par[u]][x].first]),get(en[nei[par[u]][x].first],en[par[u]])).x-2*get(st[par[u]],st[par[u]]+1).x); u=par[u]; } } ls=val+mx, w[d]=e; cout<<ls<<endl; } return 0; }