include <bits/stdc++.h>
using i64 = long long;

constexpr int N = 1e5 + 10;

std::basic_string<int> G[N];
int idx;
i64 mxw;
i64 wgt[N];
struct edge {
	int id;
	int v;
} E[N << 1];

void add(int u, int v, int eid) {
	E[++idx] = {eid, v};
	G[u] += idx;
	E[++idx] = {eid, u};
	G[v] += idx;
}

// n 条边, 进入与离开的位置。
int in[N], out[N];
i64 a[N << 1];
int tot;
void dfs(int u, int fa) {
	for (const int &i : G[u]) {
		if (E[i].v == fa)
			continue;
		a[++tot] = wgt[E[i].id];
		in[E[i].id] = tot;
		dfs(E[i].v, u);
		a[++tot] = -wgt[E[i].id];
		out[E[i].id] = tot;
	}
}

int n, m;

struct node {
	int l, r;
	i64 sum;
	i64 lans, rans;
	i64 lmax, rmin;
	i64 maxv;
	i64 ans;
} tr[N << 3];

inline void pushup(int u) {
	const node &ls = tr[u << 1], &rs = tr[u << 1 | 1];
	node &rt = tr[u];
	rt.sum = ls.sum + rs.sum;
	rt.ans = std::max({ls.ans, rs.ans, ls.rans + rs.lmax, rs.lans - ls.rmin});
	rt.lans = std::max({ls.lans, rs.lans - ls.sum, ls.maxv + rs.lmax});
	rt.rans = std::max({rs.rans, rs.sum + ls.rans, rs.maxv - ls.rmin});
	rt.lmax = std::max(ls.lmax, ls.sum + rs.lmax);
	rt.rmin = std::min(rs.rmin, rs.sum + ls.rmin);
	rt.maxv	= std::max(ls.maxv + rs.sum, rs.maxv - ls.sum);
}

void build(int u, int l, int r) {
	tr[u].l = l, tr[u].r = r;
	if (l == r) {
		tr[u].ans = tr[u].lans = tr[u].rans = abs(a[l]);
		tr[u].sum = a[l];
		tr[u].lmax = std::max(a[l], 0ll);
		tr[u].rmin = std::min(a[l], 0ll);
		tr[u].maxv = tr[u].ans;
		return ;
	}
	int mid = l + r >> 1;
	build(u << 1, l, mid);
	build(u << 1 | 1, mid + 1, r);
	pushup(u);
}

void modify(int u, int pos) {
	if (tr[u].l == tr[u].r) {
		tr[u].ans = tr[u].lans = tr[u].rans = abs(a[pos]);
		tr[u].sum = a[pos];
		tr[u].lmax = std::max(a[pos], 0ll);
		tr[u].rmin = std::min(a[pos], 0ll);
		tr[u].maxv = tr[u].ans;
		return ;
	}
	int mid = tr[u].l + tr[u].r >> 1;
	if (pos <= mid)
		modify(u << 1, pos);
	if (pos > mid)
		modify(u << 1 | 1, pos);
	pushup(u);
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);

	std::cin >> n >> m >> mxw;
	for (int i = 1; i < n; i++) {
		int u, v;
		std::cin >> u >> v >> wgt[i];
		add(u, v, i);
	}
	dfs(1, 0);
	build(1, 1, 2 * n - 2);

//	std::cout << tr[1].ans << '\n';
	i64 lst = 0;
	for (int _ = 1; _ <= m; _++) {
		int d;
		std::cin >> d;
		d = (d + lst) % (n - 1) + 1;
		std::cin >> wgt[d];
		wgt[d] = (wgt[d] + lst) % mxw;
		a[in[d]] = wgt[d];
		a[out[d]] = -wgt[d];
		modify(1, in[d]);
		modify(1, out[d]);
		lst = tr[1].ans;
		std::cout << lst << '\n';
	}
	return 0;
}

answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:10: error: ‘bits’ was not declared in this scope
    1 | include <bits/stdc++.h>
      |          ^~~~
answer.code:1:15: error: ‘stdc’ was not declared in this scope; did you mean ‘std’?
    1 | include <bits/stdc++.h>
      |               ^~~~
      |               std
answer.code:1:1: error: ‘include’ does not name a type
    1 | include <bits/stdc++.h>
      | ^~~~~~~
answer.code:6:6: error: ‘basic_string’ in namespace ‘std’ does not name a template type
    6 | std::basic_string<int> G[N];
      |      ^~~~~~~~~~~~
answer.code:1:1: note: ‘std::basic_string’ is defined in header ‘<string>’; did you forget to ‘#include <string>’?
  +++ |+#include <string>
    1 | include <bits/stdc++.h>
answer.code:8:1: error: ‘i64’ does not name a type
    8 | i64 mxw;
      | ^~~
answer.code:9:1: error: ‘i64’ does not name a type
    9 | i64 wgt[N];
      | ^~~
answer.code: In function ‘void add(int, int, int)’:
answer.code:17:9: error: ‘G’ was not declared in this scope
   17 |         G[u] += idx;
      |         ^
answer.code: At global scope:
answer.code:24:1: error: ‘i64’ does not name a type
   24 | i64 a[N << 1];
      | ^~~
answer.code: In function ‘void dfs(int, int)’:
answer.code:27:29: error: ‘G’ was not declared in this scope
   27 |         for (const int &i : G[u]) {
      |                             ^
answer.code:30:17: error: ‘a’ was not declared in this scope
   30 |                 a[++tot] = wgt[E[i].id];
      |                 ^
answer.code:30:28: error: ‘wgt’ was not declared in this scope
   30 |                 a[++tot] = wgt[E[i].id];
      |                            ^~~
answer.code: At global scope:
answer.code:42:9: error: ‘i64’ does not name a type
   42 |         i64 sum;
      |         ^~~
answer.code:43:9: error: ‘i64’ does not name a type
   43 |         i64 lans, rans;
      |         ^~~
answer.code:44:9: error: ‘i64’ does not name a type
   44 |         i64 lmax, rmin;
      |         ^~~
answer.code:45:9: error: ‘i64’ does not name a type
   45 |         i64 maxv;
      |         ^~~
answer.code:46:9: error: ‘i64’ does not name a type
   46 |         i64 ans;
      |         ^~~
answer.code: In function ‘void pushup(int)’:
answer.code:52:12: error: ‘struct node’ has no member named ‘sum’
   52 |         rt.sum = ls.sum + rs.sum;
      |            ^~~
answer.code:52:21: error: ‘const struct node’ has no member named ‘sum’
   52 |         rt.sum = ls.sum + rs.sum;
      |                     ^~~
answer.code:52:30: error: ‘const struct node’ has no member named ‘sum’
   52 |         rt.sum = ls.sum + rs.sum;
      |                              ^~~
answer.code:53:12: error: ‘struct node’ has no member named ‘ans’
   53 |   ...