#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 0x3f3f3f3f;
struct node
{
int Mi, Mj, Mk, Mij, Mjk, Mijk;
int lz;
node(int I = 0, int J = 0, int K = 0, int IJ = 0, int JK = 0, int IJK = 0, int LZ = 0) : Mi(I), Mj(J), Mk(K), Mij(IJ), Mjk(JK), Mijk(IJK), lz(LZ) {}
node operator+(node outro)
{
node resp;
resp.Mi = resp.Mk = max(Mi, outro.Mi);
resp.Mj = min(Mj, outro.Mj);
resp.Mij = max({Mij, Mi - 2*outro.Mj, outro.Mij});
resp.Mjk = max({Mjk, -2*Mj + outro.Mk, outro.Mjk});
resp.Mijk = max({Mijk, Mij + outro.Mk, Mi + outro.Mjk, outro.Mijk});
return resp;
}
};
const int MAXN = 2e5 + 10;
array<node, 4*MAXN> seg;
array<vector<pair<int, int>>, MAXN> grafo;
array<int, MAXN> peso, idIn, idOut;
int temp = 0;
void refresh(int pos, int ini, int fim)
{
if (seg[pos].lz == 0) return;
int x = seg[pos].lz; seg[pos].lz = 0;
seg[pos].Mi += x; seg[pos].Mj += x; seg[pos].Mk += x;
seg[pos].Mij -= x; seg[pos].Mjk -= x;
seg[pos].Mijk += 0;
if (ini == fim) return;
int e = 2*pos; int d = 2*pos + 1;
seg[e].lz += x;
seg[d].lz += x;
}
void update(int pos, int ini, int fim, int p, int q, int val)
{
refresh(pos, ini, fim);
if (q < ini || p > fim) return;
if (p <= ini && fim <= q)
{
seg[pos].lz += val;
refresh(pos, ini, fim);
return;
}
int m = (ini + fim) >> 1;
int e = 2*pos; int d = 2*pos + 1;
update(e, ini, m, p, q, val);
update(d, m+1, fim, p, q, val);
seg[pos] = seg[e] + seg[d];
}
node query(int pos, int ini, int fim, int p, int q)
{
refresh(pos, ini, fim);
if (q < ini || p > fim) return node(-INF, INF, -INF, -INF, -INF, -INF);
if (p <= ini && fim <= q) return seg[pos];
int m = (ini + fim) >> 1;
int e = 2*pos; int d = 2*pos + 1;
return (query(e, ini, m, p, q) + query(d, m+1, fim, p, q));
}
void dfs(int v, int p, int paiEdge)
{
++temp;
if (paiEdge != -1) idIn[paiEdge] = temp;
for (auto [viz, e] : grafo[v])
{
if (viz == p) continue;
dfs(viz, v, e);
}
++temp;
if (paiEdge != -1) idOut[paiEdge] = temp;
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N, Q, W;
cin >> N >> Q >> W;
for (int i = 1; i < N; i++)
{
int X, Y, P;
cin >> X >> Y >> P;
grafo[X].emplace_back(Y, i);
grafo[Y].emplace_back(X, i);
peso[i] = P;
}
dfs(1, 1, -1);
--temp;
for (int i = 1; i < N; i++) update(1, 1, temp, idIn[i], idOut[i]-1, peso[i]);
// node aux = query(1, 1, temp, 1, temp);
// cerr << aux.Mi << " " << aux.Mj << " " << aux.Mk << " " << aux.Mij << " " << aux.Mjk << " " << aux.Mijk << '\n';
int last = 0;
while (Q--)
{
int D, E;
cin >> D >> E;
D = (D + last) % (N - 1); ++D;
E = (E + last) % W;
update(1, 1, temp, idIn[D], idOut[D]-1, E - peso[D]);
peso[D] = E;
last = query(1, 1, temp, 1, temp).Mijk;
cout << last << '\n';
}
}
