#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define int long long
#define sm (ss + se) / 2
#define time mytime
void myassert(bool a) {
while (!a);
}
int time = -1;
ll tree[400005];
ll pend[400004];
vector<pair<int, int>> edge[100005];
vector<pair<int, int>> edge2[100005];
int depth[100005];
int in[100005], out[100005];
int par[100005];
ll old[100005];
int maksdepth;
void push(int i, int ss, int se) {
if (pend[i] != 0) {
tree[i] += pend[i];
if (ss != se) {
pend[i * 2] += pend[i];
pend[i * 2 + 1] += pend[i];
}
pend[i] = 0;
}
}
void upd(int l, int r, int val, int ss = 0, int se = 100000, int i = 1) {
myassert(l <= r);
push(i, ss, se);
if (ss > se or r < ss or l > se) return;
if (l <= ss and r >= se) {
pend[i] += val;
push(i, ss, se);
return;
}
upd(l, r, val, ss, sm, i * 2);
upd(l, r, val, sm + 1, se, i * 2 + 1);
tree[i] = max(tree[i * 2], tree[i * 2 + 1]);
}
int get(int l, int r, int ss = 0, int se = 100000, int i = 1) {
myassert(l <= r);
push(i, ss, se);
if (ss > se or ss > r or se < l) return 0;
if (ss >= l and se <= r) {
return tree[i];
}
return max(get(l, r, ss, sm, i * 2), get(l, r, sm + 1, se, i * 2 + 1));
}
// int get(int l, int r) {
// int ans = 0;
// for (int i = l; i <= r; ++i) ans = max(ans, tree[i]);
// return ans;
// }
// void upd(int l, int r, int val) {
// for (int i = l; i <= r; ++i) tree[i] += val;
// }
void rek(int cur, int prev = -1) {
maksdepth = max(maksdepth, depth[cur]);
++time;
in[cur] = time;
for (auto [i, w] : edge[cur]) {
if (i == prev) continue;
depth[i] = depth[cur] + 1;
par[i] = cur;
rek(i, cur);
}
out[cur] = time;
}
int getmaks(int i) {
if (edge[i].empty()) return 0;
int lo = 0, hi = edge[i].size();
int maks = get(in[i], out[i]);
while (lo <= hi) {
int mid = (lo + hi) / 2;
if (get(in[i], out[edge[i][mid].first]) == maks) {
hi = mid - 1;
} else lo = mid + 1;
}
int maks2 = 0;
if (lo) maks2 = max(maks2, get(in[i], out[edge[i][lo - 1].first]));
if (lo + 1 < edge[i].size()) maks2 = max(maks2, get(in[edge[i][lo + 1].first], out[i]));
// cout << maks << ' ' << maks2 << get(in[i], in[i]) << ' ' << endl;
// cout << maks + maks2 - get(in[i], in[i]) - get(in[i], in[i]) << endl;
int par = get(in[i], in[i]);
return maks - par + maks2 - (maks2 ? par : 0);
}
pair<int, int> find(int cur, int prev = -1) {
pair<int, int> res = {0, cur};
for (auto [i, w] : edge2[cur]) {
if (i == prev) continue;
auto tmp = find(i, cur);
tmp.first += w;
res = max(res, tmp);
}
return res;
}
signed main() {
int n, q, w;
cin >> n >> q >> w;
vector<pair<pair<int, int>, int>> edges;
for (int i = 0; i < n - 1; ++i) {
int u, v, w;
cin >> u >> v >> w;
--u, --v;
edge[u].push_back({v, w});
edge[v].push_back({u, w});
edge2[u].push_back({v, w});
edge2[v].push_back({u, w});
edges.push_back({{u, v}, w});
}
memset(par, -1, sizeof par);
rek(0);
// cout << maksdepth << endl;
for (int i = 0; i < n; ++i) {
// cout << depth[i] << ' ';
// upd(in[i], out[i], depth[i]);
for (auto [j, w] : edge[i]) {
if (in[j] < in[i]) continue;
// cout << in[j] << ' ' << out[j] << ' ' << w << endl;
upd(in[j], out[j], w);
}
for (int j = 0; j < edge[i].size(); ++j) {
if (edge[i][j].first == par[i]) {
// cout << i << ' ' << par[i] << endl;
edge[i].erase(edge[i].begin() + j);
break;
}
}
}
// cout << in[2] << ' ' << out[2] << endl;
// cout << getmaks(2) << endl;
// return 0;
multiset<int> all;
for (int i = 0; i < n; ++i) {
// cout << getmaks(i) << ' ';
old[i] = getmaks(i);
all.insert(old[i]);
}
// cout << endl;
// return 0;
int last = 0;
// cout << get(3, 3) << endl;
while (q--) {
int d, e;
cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
// cout << "REal " << d << ' ' << e << endl;
auto prev = edges[d];
edges[d].second = e;
auto [u, v] = prev.first;
if (in[u] > in[v]) swap(u, v);
if (n <= 5000) {
for (auto& [i, w] : edge2[u]) {
if (i == v) w = e;
}
for (auto& [i, w] : edge2[v]) {
if (i == u) w = e;
}
int tmp = find(0).second;
// cout << find(0).first << endl;
last = find(tmp).first;
cout << last << endl;
// cout << find(tmp).first << endl;
continue;
}
int cur = u;
// for (auto i : all) cout << i << ' ';
// cout << endl;
// puts("TES");
if (maksdepth < 20 and n >= 5000) {
while (cur != -1) {
// cout << getmaks(cur) << endl;
all.erase(all.find(old[cur]));
cur = par[cur];
}
}
// cout << in[v] << ' ' << out[v] << ' ' << e - prev.second << endl;
upd(in[v], out[v], e - prev.second);
if (n <= 5000) {
last = 0;
for (int i = 0; i < n; ++i) {
// cout << getmaks(i) << endl;
last = max(last, getmaks(i));
}
cout << last << endl;
continue;
}
cur = u;
if (maksdepth < 20 or n <= 5000) {
while (cur != -1) {
old[cur] = getmaks(cur);
all.insert(old[cur]);
cur = par[cur];
}
}
// cout << maks << endl;
// cout << maks + maks2 << endl;
// last = getmaks(0);
if (maksdepth < 20 or n <= 5000) {
auto it = all.end();
--it;
last = (*it);
} else {
last = getmaks(0);
}
// last = 0;
// for (int i = 0; i < n; ++i) last = max(last, getmaks(i));
cout << last << endl;
}
}
