#include <bits/stdc++.h>
using namespace std;
#define sz(x) ((int)size(x))
#define all(x) begin(x), end(x)
#define trace(x) cout << #x << ": " << (x) << endl;
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) { return (int) ((ll) rnd() % (r - l + 1)) + l; }
const int N = 100000, N_ = (1 << 18);
struct node {
ll sum = 0, mind = 0, maxd = 0, max12 = 0, max23 = 0, ans = 0;
node shift(ll x) {
return node{sum + x, mind + x, maxd + x, max12 - x, max23 - x, ans};
}
static node create(char c, ll x) {
if (c == '(') {
return node{x, 0, x, 0, x, x};
} else {
return node{-x, -x, 0, 2 * x, x, x};
}
}
} t[N_ * 2];
node mrg(node a, node b) {
b = b.shift(a.sum);
node c;
c.sum = b.sum;
c.mind = min(a.mind, b.mind);
c.maxd = max(a.maxd, b.maxd);
c.max12 = max({a.max12, b.max12, a.maxd - b.mind * 2});
c.max23 = max({a.max23, b.max23, b.maxd - a.mind * 2});
c.ans = max({a.ans, b.ans, a.max12 + b.maxd, a.maxd + b.max23});
return c;
}
int sz = 1;
string s;
ll W[N];
int op[N], cl[N], idx[N * 2], T = 0;
void init(int n) {
while (sz < n) sz <<= 1;
for (int i = 0; i < n; ++i) {
t[i + sz] = node::create(s[i], W[idx[i]]);
}
for (int i = sz - 1; i > 0; --i) {
t[i] = mrg(t[i << 1], t[i << 1 | 1]);
}
}
void modify(int i) {
t[i + sz] = node::create(s[i], W[idx[i]]);
i += sz;
i >>= 1;
while (i) {
t[i] = mrg(t[i << 1], t[i << 1 | 1]);
i >>= 1;
}
}
vector<pair<int, int>> g[N];
void dfs(int v, int p) {
for (auto [to, i] : g[v]) {
if (to != p) {
op[i] = T++;
idx[op[i]] = i;
s += '(';
dfs(to, v);
cl[i] = T++;
s += ')';
idx[cl[i]] = i;
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, q;
cin >> n >> q;
ll w;
cin >> w;
for (int i = 0; i < n - 1; ++i) {
int a, b;
cin >> a >> b;
--a, --b;
g[a].emplace_back(b, i);
g[b].emplace_back(a, i);
cin >> W[i];
}
dfs(0, -1);
init(2 * (n - 1));
ll last = 0;
while (q--) {
int i;
ll e;
cin >> i >> e;
i = (i + last) % (n - 1);
W[i] = (e + last) % w;
modify(op[i]), modify(cl[i]);
cout << (last = t[1].ans) << '\n';
}
return 0;
}
