#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define file(name) \
if(fopen(name".inp", "r")) \
freopen(name".inp", "r", stdin), freopen(name".out", "w", stdout);
template <class T> T max(T a, T b, T c) { return max(a, max(b, c)); }
const int MAX = 1e5 + 5;
struct edge {
int u, v, w;
edge(int u = 0, int v = 0, int w = 0) : u(u), v(v), w(w) {}
int get(int x) {
return u ^ x ^ v;
}
} e[MAX];
int n, q, m, time_in[MAX], time_out[MAX];
vector <int> adj[MAX];
long long W, last;
struct info {
long long max_depth, min_depth, diam, limp, rimp;
info(long long max_depth = 0,
long long min_depth = 0,
long long diam = 0,
long long limp = 0,
long long rimp = 0) :
max_depth(max_depth),
min_depth(min_depth),
diam(diam),
limp(limp),
rimp(rimp) {}
};
info operator + (const info &lhs, const info &rhs) {
info ans;
ans.max_depth = max(lhs.max_depth, rhs.max_depth);
ans.min_depth = min(lhs.min_depth, rhs.min_depth);
ans.limp = max(lhs.limp, rhs.limp, lhs.max_depth - 2 * rhs.min_depth);
ans.rimp = max(lhs.rimp, rhs.rimp, rhs.max_depth - 2 * lhs.min_depth);
ans.diam = max(lhs.diam, rhs.diam);
ans.diam = max(ans.diam, lhs.max_depth + rhs.rimp, rhs.max_depth + lhs.limp);
return ans;
}
info it[4 * MAX];
long long lazy[4 * MAX];
void apply(int idx, long long val) {
info &p = it[idx];
p.max_depth += val;
p.min_depth += val;
p.limp -= val;
p.rimp -= val;
lazy[idx] += val;
}
void push(int p) {
if(lazy[p] == 0) return;
apply(p << 1, lazy[p]);
apply(p << 1 | 1, lazy[p]);
lazy[p] = 0;
}
void update(int idx, int l, int r, int u, int v, long long val) {
if(l > v || r < u) return;
if(l >= u && r <= v) return apply(idx, val);
push(idx);
int mid = l + r >> 1;
update(idx << 1, l, mid, u, v, val);
update(idx << 1 | 1, mid + 1, r, u, v, val);
it[idx] = it[idx << 1] + it[idx << 1 | 1];
}
void dfs(int u, int p) {
static int run = 0;
run++;
for (int i : adj[u]) if(e[i].get(u) != p) {
int v = e[i].get(u);
time_in[i] = run;
dfs(v, u);
time_out[i] = run++;
update(1, 1, 2 * n, time_in[i] + 1, time_out[i], e[i].w);
}
}
void you_make_it(void) {
cin >> n >> q >> W;
for (int i = 1; i < n; ++i) {
cin >> e[i].u >> e[i].v >> e[i].w;
adj[e[i].u].push_back(i);
adj[e[i].v].push_back(i);
}
dfs(1, 0);
while(q--) {
int d; long long f; cin >> d >> f;
d = (d + last % (n - 1)) % (n - 1) + 1;
f = (f + last) % W;
update(1, 1, 2 * n, time_in[d] + 1, time_out[d], - e[d].w);
e[d].w = f;
update(1, 1, 2 * n, time_in[d] + 1, time_out[d], + e[d].w);
cout << (last = it[1].diam) << '\n';
}
}
signed main() {
#ifdef LOCAL
freopen("TASK.inp", "r", stdin);
freopen("TASK.out", "w", stdout);
#endif
file("diameter");
auto start_time = chrono::steady_clock::now();
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
you_make_it();
auto end_time = chrono::steady_clock::now();
cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;
return (0 ^ 0);
}
// Dream it. Wish it. Do it.
