#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 2023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef pair<ll,int> li;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));
#define mod 1000000007
inline int add(int a,int b){
int r=a+b;
while(r>=mod)r-=mod;
while(r<0)r+=mod;
return r;
}
inline int mult(int a,int b){
return (int)(((ll)(a*b))%mod);
}
inline int rd(){
int x=0;
char ch=getchar_unlocked();
while(!(ch&16))ch=getchar();//keep reading while current character is whitespace
while(ch&16){//this will break when ‘\n’ or ‘ ‘ is encountered
x=(x<<3)+(x<<1)+(ch&15);
ch=getchar_unlocked();
}
return x;
}
#define maxn 100005
struct edge{
int u,v;ll w;
vector<int> comp;
vector<ii> range;
};
struct node{
int s,e;ll ans;
vector<li> v;
vector<ll> lz;
vector<ii> ranges;
void init(int i,int l,int r){
v[i]={0,l};
lz[i]=0;
if(l==r)return;
int m=(l+r)>>1;
init(2*i+1,l,m);
init(2*i+2,m+1,r);
}
node(int _s,int _e){
s=_s;e=_e;
v.resize(4*(e-s+1));
lz.resize(4*(e-s+1),0);
ranges.resize(e-s+1);
init(0,s,e);
}
void ppo(int i,int l,int r){
v[i].fi+=lz[i];
if(l!=r){
lz[2*i+1]+=lz[i];
lz[2*i+2]+=lz[i];
}
lz[i]=0;
}
void up(int i,int l,int r,int x,int y,ll nv){
//pf("up: %d %d %d %d %d %lld\n",i,l,r,x,y,nv);
if(l==x&&r==y){
lz[i]+=nv;return;
}
int m=(l+r)>>1;
if(y<=m)up(2*i+1,l,m,x,y,nv);
else if(x>m)up(2*i+2,m+1,r,x,y,nv);
else{
up(2*i+1,l,m,x,m,nv);
up(2*i+2,m+1,r,m+1,y,nv);
}
//pf("left child: %lld %d %lld\n",v[2*i+1].fi,v[2*i+1].se,lz[2*i+1]);
//pf("right child: %lld %d %lld\n",v[2*i+2].fi,v[2*i+2].se,lz[2*i+2]);
ppo(2*i+1,l,m);ppo(2*i+2,m+1,r);
//pf("%d %d old val: %lld %d\n",l,r,v[i].fi,v[i].se);
v[i]=max(v[2*i+1],v[2*i+2]);
//pf("%d %d new val: %lld %d\n",l,r,v[i].fi,v[i].se);
//pf("left child: %lld %d\n",v[2*i+1].fi,v[2*i+1].se);
//pf("right child: %lld %d\n",v[2*i+2].fi,v[2*i+2].se);
}
void up(int x,int y,ll nv){
//pf("up: %d %d %lld\n",x,y,nv);
up(0,s,e,x,y,nv);
}
void print(int i,int l,int r){
//pf("node: %d %d %d %lld %d %lld\n",i,l,r,v[i].fi,v[i].se,lz[i]);
int m=(l+r)>>1;
if(l!=r)print(2*i+1,l,m),print(2*i+2,m+1,r);
}
ll qry(){
//pf("qry:\n");
ans=v[0].fi+lz[0];
//pf("%lld %d\n",v[0].fi,v[0].se);
int i=v[0].se;
up(ranges[i].fi,ranges[i].se,-LINF);
//pf("%lld %d\n",v[0].fi,v[0].se);
if(v[0].fi+lz[0]>=0)ans+=v[0].fi+lz[0];
up(ranges[i].fi,ranges[i].se,LINF);
return ans;
}
}*root[maxn];
int n,q,sub[maxn];ll w;
bool mark[maxn];
vii AL[maxn];
vector<edge> edges;
void find_sz(int u,int p){
sub[u]=1;
for(auto[v,i]:AL[u]){
if(mark[v]||v==p)continue;
find_sz(v,u);
sub[u]+=sub[v];
}
}
int cnt;
vii ranges;
ii dfs(int u,int p,int c){
ii range={cnt,cnt};++cnt;
for(auto[v,i]:AL[u]){
if(mark[v]||v==p)continue;
ii res=dfs(v,u,c);
edges[i].comp.pb(c);
edges[i].range.pb(res);
mxto(range.se,res.se);
if(p==-1)ranges.pb(res);
}
return range;
}
void decomp(int u){
find_sz(u,-1);
int c=u;
while(true){
bool val=true;
for(auto[v,i]:AL[u]){
if(!mark[v]&&sub[v]<sub[c]&&sub[v]>=sub[u]/2){
c=v;val=false;break;
}
}
if(val)break;
}
cnt=0;
ranges.clear();
dfs(c,-1,c);
root[c]=new node(0,cnt-1);
for(int i=0;i<sz(ranges);++i){
for(int j=ranges[i].fi;j<=ranges[i].se;++j){
root[c]->ranges[j]=ranges[i];
}
}
mark[c]=true;
for(auto[v,i]:AL[c]){
if(!mark[v])decomp(v);
}
}
int main(){
sf("%d%d%lld",&n,&q,&w);
for(int i=0;i<n-1;++i){
int a,b;ll c;
sf("%d%d%lld",&a,&b,&c);
AL[a].pb({b,i});
AL[b].pb({a,i});
edges.pb({a,b,c,{},{}});
}
decomp(1);
for(edge &e:edges){
for(int i=0;i<sz(e.comp);++i){
ii rng=e.range[i];
//root[e.comp[i]]->print(0,root[e.comp[i]]->s,root[e.comp[i]]->e);
root[e.comp[i]]->up(rng.fi,rng.se,e.w);
//root[e.comp[i]]->print(0,root[e.comp[i]]->s,root[e.comp[i]]->e);
}
}
set<li> s;
for(int i=1;i<=n;++i){
s.insert({root[i]->qry(),i});
//pf("init: %lld %d\n",root[i]->qry(),i);
}
//pf("-------------start--------------\n");
ll ans=0;
while(q--){
ll idx,nw;
sf("%lld%lld",&idx,&nw);
idx=(idx+ans)%(n-1);
nw=(nw+ans)%w;
edge &e=edges[idx];
ll ow=e.w;
e.w=nw;
//dbg("upd: %d %lld\n",idx,nw);
for(int i=0;i<sz(e.comp);++i){
ii rng=e.range[i];
int c=e.comp[i];
ll old=root[c]->ans;
root[c]->up(rng.fi,rng.se,nw-ow);
ll upd=root[c]->qry();
s.erase(s.find({old,c}));
s.insert({upd,c});
}
ans=(*--s.end()).fi;
pf("%lld\n",ans);
}
}
