#include <cstdio>
#include <array>
#include <vector>
#include <utility>
const int N = 200005, N_ = N * 4;
template <typename T>
using ve=std::vector<T>;
template <typename T,unsigned sz>
using ar=std::array<T,sz>;
using il=std::pair<int, long long>;
using ii=std::pair<int, int>;
using ll=long long;
int n, q, i, u, v, d;
ll W, x, ww[N], e;
ve<int> h[N];
enum Type{VERTEX,RAKE,COMPRESS,ADDEDGE,ADDVERTEX};
struct {
int p[N_],l[N_],r[N_],root,alc;
Type T[N_];
void init(){
alc=2*n;
dfs(0);
root=compress(0).first;
}
int add(int k,int lc,int rc,Type t){
if(!~k)k=alc++;
p[k]=-1,l[k]=lc,r[k]=rc,T[k]=t;
if(~lc)p[lc]=k;if(~rc)p[rc]=k;
return k;
}
ii merge(ve<ii>l,Type t){
if(l.size()==1)return l[0];
int sz=0;
for(auto[u,s]:l)sz+=s;
ve<ii>b,c;
for(auto[u,s]:l)(sz>s?b:c).emplace_back(u,s),sz-=2*s;
auto[i,si]=merge(b,t);
auto[j,sj]=merge(c,t);
return{add(-1,i,j,t),si+sj};
}
ii compress(int i){
ve<ii>pat{add_vertex(i)};
for(;h[i].size();)pat.push_back(add_vertex(i=h[i][0]));
return merge(pat,COMPRESS);
}
ii rake(int i){
ve<ii>chs;
for(int j=1;j<(int)h[i].size();++j)chs.push_back(add_edge(h[i][j]));
return chs.empty()?ii{-1,0}:merge(chs,RAKE);
}
ii add_edge(int i){
auto[j,sj]=compress(i);
return{add(-1,j,-1,ADDEDGE),sj};
}
ii add_vertex(int i){
auto[j,sj]=rake(i);
return{add(i,j,-1,j==-1?VERTEX:ADDVERTEX),sj+1};
}
int dfs(int u){
int s=1,t,q=0;
for(int j=0;j<(int)h[u].size();++j){
s+=(t=dfs(h[u][j]));
if(q<t)std::swap(h[u][j],h[u][0]),q=t;
}
return s;
}
} stt;
using Pat=ar<ll,2>;
using Poi=ar<ll,2>;
Pat pat[N_];
Poi poi[N_];
Pat vertex(int v){
return{ww[v],0};
}
Pat compress(Pat i,Pat j){
Pat z{i};
if(j[1]>=z[0])z[1]=z[0],z[0]=j[1];
else if(j[1]>z[1])z[1]=j[1];
if(j[0]>=z[0])z[1]=z[0],z[0]=j[0];
else if(j[0]>z[1])z[1]=j[0];
return z;
}
Poi rake(Poi i,Poi j){
Poi z{i};
if(j[1]>=z[0])z[1]=z[0],z[0]=j[1];
else if(j[1]>z[1])z[1]=j[1];
if(j[0]>=z[0])z[1]=z[0],z[0]=j[0];
else if(j[0]>z[1])z[1]=j[0];
return z;
}
Pat add_vertex(Poi t,int v){
return {t[0]+ww[v],t[1]+ww[v]};
}
Poi add_edge(Pat t){
return {t[0],0};
}
void upd(int u){
switch(stt.T[u]){
case VERTEX:
pat[u]=vertex(u);
break;
case RAKE:
poi[u]=rake(poi[stt.l[u]],poi[stt.r[u]]);
break;
case COMPRESS:
pat[u]=compress(pat[stt.l[u]],pat[stt.r[u]]);
break;
case ADDEDGE:
poi[u]=add_edge(pat[stt.l[u]]);
break;
case ADDVERTEX:
pat[u]=add_vertex(poi[stt.l[u]],u);
break;
}
}
void dfs0(int u){
if(!~u)return;
dfs0(stt.l[u]),dfs0(stt.r[u]);
upd(u);
}
int main() {
scanf("%d%d%lld", &n, &q, &W);
/*->generate modified rooted tree with 2*n+1 vertices */
{
ve<ve<ar<ll,3>>> g(N);int alc=n;
for (i = 1; i < n; ++i)
scanf("%d%d%lld", &u, &v, &x), --u, --v, g[u].emplace_back(ar<ll,3>{v, x, i - 1}), g[v].emplace_back(ar<ll,3>{u, x, i - 1});
auto dfs=[&](auto&&dfs,int u,int p,ll w,int id)->void{
for (auto [v, w, id] : g[u]) if (v != p)
dfs(dfs,v, u, w,id);
if (u != p) {
id+=n;
h[id].push_back(u);
h[p].push_back(id);
ww[id] = w;
}
};
dfs(dfs, 0, 0, 0,-1);
}
stt.init();
dfs0(stt.root);
ll last=0;
while(q--){
scanf("%d%lld",&d,&e);
d=(d+last)%(n-1);--d;
e=(e+last)%W;
ww[d+=n-1]=e;
for(;d!=-1;d=stt.p[d])upd(d);
printf("%lld\n",last=pat[stt.root][0]+pat[stt.root][1]);
}
}
