#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
#define int long long
const int M = 1<<17, N = (1<<22) + 1;
int Max[N<<1], Lz[N<<1], dead[M], ch[M], cr = 1, Ed[M], Wei[M], last;
vector<pair<int, int>> nei[M], Rng[M], Top[M];
vector<int> Par[M];
multiset<int> st[M], stAns;
void Push(int cur, int lc, int rc){
Max[lc] += Lz[cur], Lz[lc] += Lz[cur];
Max[rc] += Lz[cur], Lz[rc] += Lz[cur];
Lz[cur] = 0;
}
void Add(int l, int r, int v, int cur = 1, int st = 1, int en = N){
if (l >= en or r <= st)
return;
if (l <= st and r >= en){
Max[cur] += v, Lz[cur] += v;
return;
}
int lc = cur<<1, rc = lc|1, mid = (st + en) >> 1;
Push(cur, lc, rc);
Add(l, r, v, lc, st, mid);
Add(l, r, v, rc, mid, en);
Max[cur] = max(Max[lc], Max[rc]);
}
int getMax(int l, int r, int cur = 1, int st = 1, int en = N){
if (l >= en or r <= st)
return 0;
if (l <= st and en <= r)
return Max[cur];
int lc = cur<<1, rc = lc|1, mid = (st + en) >> 1;
Push(cur, lc, rc);
return max(getMax(l, r, lc, st, mid), getMax(l, r, rc, mid, en));
}
int dfs1(int u, int p){
for (auto [i, id] : nei[u])
if (i != p and !dead[i])
ch[u] += dfs1(i, u);
return ++ch[u];
}
int cent(int u, int p, int rs){
for (auto [i, id] : nei[u])
if (i != p and !dead[i] and ch[i] * 2 > rs)
return cent(i, u, rs);
return u;
}
void dfs2(int u, int p, int C){
for (auto [i, id] : nei[u]){
if (i == p or dead[i])
continue;
int st = cr++;
Par[id].push_back(C);
dfs2(i, u, C);
Rng[id].push_back({st, cr});
}
}
void dfs3(int u, int p, pair<int, int> pr, int Id){
Top[Id].push_back(pr);
for (auto [i, id] : nei[u])
if (i != p and !dead[i])
dfs3(i, u, pr, id);
}
void decompose(int u){
dfs1(u, u);
int c = cent(u, u, ch[u]);
dfs2(c, -1, c);
dead[c] = 1;
st[c] = {0, 0};
for (auto [i, id] : nei[c]){
if (dead[i])
continue;
st[c].insert(0);
dfs3(i, c, Rng[id].back(), id);
}
stAns.insert(0);
for (auto [i, id] : nei[c])
if (!dead[i])
decompose(i);
}
void Upd(int id, int w){
for (int i=0;i<Par[id].size();i++){
auto [l1, r1] = Rng[id][i];
auto [l2, r2] = Top[id][i];
int C = Par[id][i];
stAns.erase(stAns.find(*rbegin(st[C]) + *next(rbegin(st[C]))));
st[C].erase(st[C].find(getMax(l2, r2)));
Add(l1, r1, w - Wei[id]);
st[C].insert(getMax(l2, r2));
stAns.insert(*rbegin(st[C]) + *next(rbegin(st[C])));
}
Wei[id] = w;
}
signed main(){
ios_base::sync_with_stdio(false); cin.tie(NULL);
int n, q, w;
cin>>n>>q>>w;
for (int i=1, a, b;i<n;i++){
cin>>a>>b>>Ed[i];
nei[a].push_back({b, i});
nei[b].push_back({a, i});
}
decompose(1);
for (int i=1;i<n;i++)
Upd(i, Ed[i]);
for (int i=1, a, b;i<=q;i++){
cin>>a>>b;
a = (a + last) % (n - 1) + 1;
b = (b + last) % w;
Upd(a, b);
last = *rbegin(stAns);
cout<<last<<'\n';
}
}
