#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC target ("avx2")
#define pb push_back
#define rc (i<<1)|1
#define lc (i<<1)
#define el "\n"
#define f first
#define s second
typedef long long ll;
const int MM=1e5+5, MOD=1e9+7, LOG=19;
int N, Q, sz[MM], bk[MM], pa[MM], in[LOG][MM], ot[LOG][MM], cp[LOG][MM], tp[LOG][MM], ct;
vector<int> adj[MM]; ll av[MM], W;
gp_hash_table<int,int> mp[MM];
multiset<ll> ast;
struct node {
ll lz;
pair<ll,int> mx;
};
struct tree {
vector<node> seg;
int wt;
inline void prop(int i, int l, int r) {
if(l!=r) {
seg[lc].lz+=seg[i].lz;
seg[rc].lz+=seg[i].lz; }
seg[i].mx.f+=seg[i].lz;
seg[i].lz=0;
}
void build(int i, int sl, int sr) {
if(sl==sr) {
seg[i].mx=make_pair(0,sl);
return; }
int m=sl+sr>>1;
build(rc, m+1, sr);
build(lc, sl, m);
calc(i);
}
inline void calc(int i) {
seg[i].mx=max(seg[lc].mx, seg[rc].mx);
}
void upd(int i, int sl, int sr, int l, int r, ll v) {
prop(i, sl, sr);
if(l>sr || r<sl) return;
if(l<=sl&&sr<=r) {
seg[i].lz+=v;
prop(i, sl, sr); return; }
int m=sl+sr>>1;
upd(rc, m+1, sr, l, r, v);
upd(lc, sl, m, l, r, v);
calc(i);
}
pair<ll,int> rmq(int i, int sl, int sr, int l, int r) {
prop(i, sl, sr);
if(l>sr || r<sl) return {0,0};
if(l<=sl&&sr<=r) return seg[i].mx;
int m=sl+sr>>1;
return max(rmq(lc, sl, m, l, r), rmq(rc, m+1, sr, l, r));
}
void init(int n) {
wt=n;
seg.resize(4*n+4);
build(1, 1, n);
}
} st[MM];
int crt(int u, int th, int fa) {
for(int &v:adj[u]) if(v!=fa&&!bk[v]&&sz[v]>th) {
return crt(v, th, u); }
return u;
}
void dfs(int u, int fa) {
sz[u]=1;
for(int &v:adj[u]) if(v!=fa&&!bk[v]) {
dfs(v, u);
sz[u]+=sz[v];
}
}
void etr(int u, int fa, int lvl, int rt, int tv) {
in[lvl][u]=++ct; cp[lvl][u]=rt; tp[lvl][u]=tv; mp[rt][ct]=u;
for(int &v:adj[u]) if(v!=fa&&!bk[v]) {
etr(v, u, lvl, rt, tv); }
ot[lvl][u]=ct;
}
void rec(int rt, int nds, int fa=-1, int lvl=0) {
if(nds<=1) return;
dfs(rt, 0);
// cout<<"centroid for "<<rt<<" nds "<<nds<<" lvl "<<lvl<<" is ";
rt=crt(rt, nds/2, 0); pa[rt]=fa;
// cout<<rt<<el;
bk[rt]=true; ct=0;
// get ett
cp[lvl][rt]=tp[lvl][rt]=rt;
for(int &v:adj[rt]) if(!bk[v]) etr(v, rt, lvl, rt, v);
if(ct==0) return;
// construct tree
st[rt].init(nds);
int tally=0, lv=-1;
for(int &v:adj[rt]) if(!bk[v]) {
if(sz[v]<sz[rt]) {
tally+=sz[v];
rec(v, sz[v], rt, lvl+1);
} else lv=v;
}
if(~lv) rec(lv, nds-tally-1, rt, lvl+1);
}
void qry(int u, int v, ll val) {
// find smallest component
int cur=0;
while(cur<LOG-1&&cp[cur+1][u]==cp[cur+1][v]&&cp[cur+1][u]!=0) ++cur;
// cout<<"iterating on "<<u<<" starting with "<<cur<<" delta "<<val<<el;
// jump
int crt=cp[cur][u];
while(cur>=0) {
// update edge
// cout<<"crt "<<crt<<el;
int w=(in[cur][u]>in[cur][v]?u:v);
// cout<<"level "<<cur<<" w "<<w<<" cent "<<crt<<" updating "<<in[cur][w]<<" "<<ot[cur][w]<<el;
st[crt].upd(1, 1, st[crt].wt, in[cur][w], ot[cur][w], val);
// query max
auto x=st[crt].rmq(1, 1, st[crt].wt, 1, st[crt].wt);
x.s=mp[crt][x.s];
// cout<<"x value "<<x.f<<" "<<x.s<<" "<<tp[cur][x.s]<<" "<<in[cur][tp[cur][x.s]]<<" "<<ot[cur][tp[cur][x.s]]<<el;
auto y=max(st[crt].rmq(1, 1, st[crt].wt, 1, in[cur][tp[cur][x.s]]-1), st[crt].rmq(1, 1, st[crt].wt, ot[cur][tp[cur][x.s]]+1, st[crt].wt));
//cout<<"y value "<<y.f<<" "<<x.s<<el;
ll cnd=x.f+y.f;
if(cnd!=av[crt]) {
ast.erase(ast.find(av[crt]));
ast.insert(av[crt]=cnd);
}
crt=pa[crt]; cur--;
}
}
int32_t main() {
cin.tie(nullptr)->sync_with_stdio(false);
cin>>N>>Q>>W;
vector<pair<ll,pair<int,int>>> edg;
for(int i=1; i<N; ++i) {
ll u, v, w; cin>>u>>v>>w;
adj[u].pb(v); adj[v].pb(u);
edg.pb({w,{u,v}});
}
// preprocess
rec(1, N);
for(int i=1; i<=N; ++i) ast.insert(0);
for(auto &e:edg) qry(e.s.f, e.s.s, e.f);
ll last=0, e, w;
for(int q=1; q<=Q; ++q) {
cin>>e>>w;
e=(e+last)%(N-1);
w=(w+last)%W;
qry(edg[e].s.f, edg[e].s.s, w-edg[e].f);
last=*ast.rbegin(); edg[e].f=w;
cout<<last<<el;
}
}
