#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <functional>
using namespace std;
#pragma warning (disable: 4996)
class LazySegmentTree {
public:
int size_ = 1;
vector<long long> dat, lazy;
void init(int sz) {
while (size_ <= sz) size_ *= 2;
dat.resize(size_ * 2, 0);
lazy.resize(size_ * 2, 0);
}
void refresh(int u) {
if (u < size_) {
lazy[u * 2 + 0] += lazy[u];
lazy[u * 2 + 1] += lazy[u];
lazy[u] = 0;
dat[u] = max(dat[u * 2] + lazy[u * 2], dat[u * 2 + 1] + lazy[u * 2 + 1]);
}
else {
dat[u] += lazy[u];
lazy[u] = 0;
}
}
void add_(int l, int r, long long x, int a, int b, int u) {
if (l <= a && b <= r) { lazy[u] += x; return; }
if (r <= a || b <= l) return;
refresh(u);
add_(l, r, x, a, (a + b) >> 1, u * 2);
add_(l, r, x, (a + b) >> 1, b, u * 2 + 1);
refresh(u);
}
void add(int l, int r, long long x) {
add_(l, r, x, 0, size_, 1);
}
long long query_(int l, int r, int a, int b, int u) {
if (l <= a && b <= r) return dat[u] + lazy[u];
if (r <= a || b <= l) return -(1LL << 60);
refresh(u);
long long v1 = query_(l, r, a, (a + b) >> 1, u * 2);
long long v2 = query_(l, r, (a + b) >> 1, b, u * 2 + 1);
refresh(u);
return max(v1, v2);
}
long long query(int l, int r) {
return query_(l, r, 0, size_, 1);
}
};
// Input
long long N, A[1 << 18], B[1 << 18], C[1 << 18];
long long Q, D[1 << 18], E[1 << 18];
long long W;
vector<pair<int, long long>> X[1 << 18];
// Some Information
long long dist[1 << 18];
// Subtask 2
void dfs1(int pos, long long dep) {
dist[pos] = dep;
for (int i = 0; i < X[pos].size(); i++) {
if (dist[X[pos][i].first] != (1LL << 60)) continue;
dfs1(X[pos][i].first, dep + X[pos][i].second);
}
}
void getdist(int pos) {
for (int i = 1; i <= N; i++) dist[i] = (1LL << 60);
dfs1(pos, 0);
}
long long solve1() {
for (int i = 1; i <= N; i++) X[i].clear();
for (int i = 1; i <= N - 1; i++) {
X[A[i]].push_back(make_pair(B[i], C[i]));
X[B[i]].push_back(make_pair(A[i], C[i]));
}
getdist(1);
pair<long long, int> maxn1 = make_pair(-1, -1);
for (int i = 1; i <= N; i++) maxn1 = max(maxn1, make_pair(dist[i], i));
getdist(maxn1.second);
pair<long long, int> maxn2 = make_pair(-1, -1);
for (int i = 1; i <= N; i++) maxn2 = max(maxn2, make_pair(dist[i], i));
return maxn2.first;
}
void solve_subtask2() {
long long last = 0;
for (int i = 1; i <= Q; i++) {
D[i] = (D[i] + last) % (N - 1LL) + 1LL;
E[i] = (E[i] + last) % W;
C[D[i]] = E[i];
last = solve1();
printf("%lld\n", last);
}
}
int cnts, cl[1 << 18], cr[1 << 18], depth[1 << 18], idx[1 << 18];
vector<int> Y[1 << 18];
LazySegmentTree Z;
set<pair<long long, int>> Set;
void dfs2(int pos, int dep) {
depth[pos] = dep;
cnts++; cl[pos] = cnts;
for (int i = 0; i < X[pos].size(); i++) {
if (cl[X[pos][i].first] >= 1) continue;
Y[pos].push_back(X[pos][i].first);
dfs2(X[pos][i].first, dep + 1);
}
cr[pos] = cnts;
}
void dfs3(int pos, int id) {
idx[pos] = id;
for (int i : Y[pos]) dfs3(i, id);
}
void solve_subtask5() {
dfs2(1, 0);
for (int i = 0; i < Y[1].size(); i++) dfs3(Y[1][i], Y[1][i]);
Z.init(N + 2);
for (int i = 1; i <= N - 1; i++) {
if (depth[A[i]] > depth[B[i]]) swap(A[i], B[i]);
Z.add(cl[B[i]], cr[B[i]] + 1, C[i]);
}
for (int i = 0; i < Y[1].size(); i++) {
long long val = Z.query(cl[Y[1][i]], cr[Y[1][i]] + 1);
Set.insert(make_pair(val, Y[1][i]));
}
long long last = 0;
for (int i = 1; i <= Q; i++) {
D[i] = (D[i] + last) % (N - 1LL) + 1LL;
E[i] = (E[i] + last) % W;
long long changes = E[i] - C[D[i]];
long long pos = B[D[i]];
long long root = idx[B[D[i]]];
long long val1 = Z.query(cl[root], cr[root] + 1);
Set.erase(make_pair(val1, root));
Z.add(cl[pos], cr[pos] + 1, changes);
long long val2 = Z.query(cl[root], cr[root] + 1);
Set.insert(make_pair(val2, root));
long long r = 0; auto itr = Set.end();
for (int t = 1; t <= 2; t++) {
if (itr == Set.begin()) break;
itr--;
r += (*itr).first;
}
last = r; C[D[i]] = E[i];
printf("%lld\n", r);
}
}
long long maxdist[1 << 18];
long long val[1 << 18];
priority_queue<pair<long long, int>, vector<pair<long long, int>>, less<pair<long long, int>>> Que;
void solve_subtask4() {
for (int i = 1; i <= N - 1; i++) val[B[i]] = C[i];
for (int i = N / 2; i >= 1; i--) maxdist[i] = max(maxdist[i * 2] + val[i * 2], maxdist[i * 2 + 1] + val[i * 2 + 1]);
for (int i = 1; i <= N / 2; i++) Que.push(make_pair(maxdist[i * 2] + val[i * 2] + maxdist[i * 2 + 1] + val[i * 2 + 1], i));
long long last = 0;
for (int i = 1; i <= Q; i++) {
D[i] = (D[i] + last) % (N - 1LL) + 1LL;
E[i] = (E[i] + last) % W;
int pos = B[D[i]]; val[pos] = E[i];
while (pos >= 2) {
pos >>= 1;
maxdist[pos] = max(maxdist[pos * 2] + val[pos * 2], maxdist[pos * 2 + 1] + val[pos * 2 + 1]);
Que.push(make_pair(maxdist[pos * 2] + val[pos * 2] + maxdist[pos * 2 + 1] + val[pos * 2 + 1], pos));
}
while (!Que.empty()) {
pair<long long, int> R = Que.top();
if (maxdist[R.second * 2] + val[R.second * 2] + maxdist[R.second * 2 + 1] + val[R.second * 2 + 1] != R.first) Que.pop();
else break;
}
last = Que.top().first;
printf("%lld\n", last);
}
}
int main() {
scanf("%lld%lld%lld", &N, &Q, &W); bool flag = false;
for (int i = 1; i <= N - 1; i++) {
scanf("%lld%lld%lld", &A[i], &B[i], &C[i]); if (A[i] > B[i]) swap(A[i], B[i]);
if (B[i] - 2LL * A[i] < 0 || 1 < B[i] - 2LL * A[i]) flag = true;
X[A[i]].push_back(make_pair(B[i], C[i]));
X[B[i]].push_back(make_pair(A[i], C[i]));
}
for (int i = 1; i <= Q; i++) scanf("%lld%lld", &D[i], &E[i]);
if (N <= 5000 && Q <= 5000) {
solve_subtask2();
}
else if (flag == false) {
solve_subtask4();
}
else {
solve_subtask5();
}
return 0;
}
