#include <bits/stdc++.h>
using namespace std;
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>;
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, q;
long long w;
cin >> n >> q >> w;
vector<tuple<int, int, long long>> edges(n);
vector<long long> seg(n * 4);
vector<long long> mx(n * 4);
for (int i = 1; i < n; i++)
{
auto &[u, v, c] = edges[i];
cin >> u >> v >> c;
}
vector adj(n + 1, vector<pair<int, long long>>());
vector<pair<long long, long long>> ee(n, make_pair(0, 0));
for (int i = 1; i < n; i++)
{
auto &[u, v, c] = edges[i];
if (u > v)
swap(u, v);
if (v == u * 2)
ee[u].first = c;
else
ee[u].second = c;
}
for (int i = n - 1; i >= 0; i--)
{
int v = i;
seg[v] = max(seg[v * 2] + ee[v].first, seg[v * 2 + 1] + ee[v].second);
mx[v] = max({mx[v * 2], mx[v * 2 + 1], seg[v * 2] + ee[v].first + seg[v * 2 + 1] + ee[v].second});
}
// how to find the diameter?
// run two dfs
auto find_diameter = [&]() -> long long
{
vector adj(n + 1, vector<pair<int, long long>>());
for (int i = 1; i < n; i++)
{
auto [u, v, c] = edges[i];
adj[u].push_back({v, c});
adj[v].push_back({u, c});
}
vector<long long> dis(n + 1, 0);
auto dfs = [&](auto self, int u, int p) -> void
{
for (auto [v, c] : adj[u])
{
if (v == p)
continue;
dis[v] = dis[u] + c;
self(self, v, u);
}
};
dfs(dfs, 1, -1);
int mx = max_element(dis.begin(), dis.end()) - dis.begin();
dis[mx] = 0;
dfs(dfs, mx, -1);
mx = max_element(dis.begin(), dis.end()) - dis.begin();
return dis[mx];
};
long long lst = 0;
multiset<long long> st;
for (int i = 1; i < n; i++)
{
auto &[u, v, c] = edges[i];
st.insert(c);
}
while (q--)
{
int d;
long long e;
cin >> d >> e;
d = (d + lst) % (n - 1) + 1;
e = (e + lst) % w;
auto &[u, vv, c] = edges[d];
c = e;
if (vv == u * 2)
ee[u].first = c;
else
ee[u].second = c;
int v = u;
while (v)
{
seg[v] = max(seg[v * 2] + ee[v].first, seg[v * 2 + 1] + ee[v].second);
mx[v] = max({mx[v * 2], mx[v * 2 + 1], seg[v * 2] + ee[v].first + seg[v * 2 + 1] + ee[v].second});
v /= 2;
}
cout << mx[1] << '\n';
lst = mx[1];
continue;
st.erase(st.find(c));
c = e;
st.insert(c);
if (n == 2)
{
cout << *prev(st.end()) << '\n';
lst = *prev(st.end());
continue;
}
cout << *prev(st.end()) + *prev(prev(st.end())) << '\n';
lst = *prev(st.end()) + *prev(prev(st.end()));
continue;
long long res = find_diameter();
cout << res << '\n';
lst = res;
}
}
