#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#include<bits/stdc++.h>
#include<math.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<ll, ll> pl;
#define K first
#define V second
#define G(x) ll x; cin >> x;
#define GD(x) ld x; cin >> x;
#define GS(s) string s; cin >> s;
#define EX(x) { cout << x << '\n'; exit(0); }
#define A(a) (a).begin(), (a).end()
#define F(i, l, r) for (ll i = (l); i < r; ++i)
#define NN 100010
#define M 1000000007 // 998244353
vector<pl> adj[NN];
ll belong[NN], w[NN]; // maps original edge -> which edge it belongs to now
ll down[NN], par[NN]; // in the new tree, the node below edge I = down[i], and parent of node X in new tree
ll parEdge[NN]; // wehn traversing par, what is the edge I use
ll curw[NN]; // current weight of edge
ll edgeidx = 0;
void dfs(ll i, ll p, ll vpar) {
ll children = 0;
for (auto [x, _]: adj[i]) if (x-p) children++;
if (children == 1) {
for (auto [x, eidx]: adj[i]) if (x-p) {
belong[eidx] = edgeidx;
dfs(x, i, vpar);
}
} else {
if (i != p) {
down[edgeidx] = i;
par[i] = vpar;
parEdge[i] = edgeidx;
edgeidx++;
}
for (auto [x, eidx]: adj[i]) if (x-p) {
belong[eidx] = edgeidx;
dfs(x, i, i);
}
}
}
struct my_multiset {
map<ll, ll> cont; // underlying container
ll sz = 0;
void insert(ll v) {
cont[v]++;
++sz;
}
void erase(ll v) {
if (!--cont[v]) cont.erase(v);
--sz;
}
ll size() const {
return sz;
}
ll maximum() const {
return cont.rbegin()->K;
}
ll max2() const {
assert(sz>=2);
if (cont.rbegin()->V >= 2) return cont.rbegin()->K*2;
return cont.rbegin()->K + (*++cont.rbegin()).K;
}
};
my_multiset all_answer; // all subtree answers
ll curans[NN]; //current answer
my_multiset childrenPull[NN]; // the curD's of my children
vector<pl> children[NN]; // children -> curD
ll ROOT(ll i) {
return par[i] == i || par[i] == -1;
}
ll getOneEdge(ll i) { // CANNOT be 1
if (childrenPull[i].size() == 0) return 0;
return childrenPull[i].maximum();
}
void recompute(ll i, ll modified) {
// cout << "asking to recompute " << i << " with child " << modified << " modified " << endl;
// cout << "lol " << i << " " << modified << endl;
// recomptues maximal down
// cout << "LOL " << childrenPull[i].size() << ": ";
// for (auto x: childrenPull[i]) cout << x << " , "; cout << endl;
auto it = lower_bound(A(children[i]), pl{modified, -1});
childrenPull[i].erase(it->V);
it->V = curw[parEdge[modified]] + getOneEdge(modified);
childrenPull[i].insert(it->V);
all_answer.erase(curans[i]);
if (childrenPull[i].size() <= 1)
curans[i] = 0;
else {
// cout << "YA " << childrenPull[i].maximum() << ", " << childrenPull[i].max2() << " for " << i << " " << modified << endl;
curans[i] = childrenPull[i].max2();
}
all_answer.insert(curans[i]);
if (!ROOT(i)) recompute(par[i], i);
}
int main(){
// freopen("a.in", "r", stdin);
// freopen("a.out", "w", stdout);
ios_base::sync_with_stdio(false); cin.tie(0);
cout << fixed << setprecision(20);
G(n) G(q) G(W)
memset(par, -1, sizeof par);
vector<ll> weights(n-1);
F(i, 0, n-1) {
G(x) G(y) cin >> weights[i];
adj[x].emplace_back(y, i);
adj[y].emplace_back(x, i);
}
// We want to dfs from a non-leaf root node.
// Unless n=2; then it's trivial.
if (n==2) {
ll last = 0;
while (q--) {
G(d) G(e)
d = (d + last)%(n-1);
e = (e + last)%W;
last = e;
cout << last << '\n';
}
exit(0);
}
F(root, 1, n+1) if (adj[root].size() >1) {
dfs(root, -1, root); break;
}
F(i, 1, n+1) if (~par[i]) {
if (!ROOT(i)) {
children[par[i]].emplace_back(i, 0);
childrenPull[par[i]].insert(0);
}
}
F(i, 1, n+1) if (~par[i]) {
sort(A(children[i]));
if (children[i].size()) {
all_answer.insert(curans[i] = 0);
}
}
set<ll> toprocess;
F(i, 0, n-1) {
curw[belong[i]] += (w[i] = weights[i]);
toprocess.insert(belong[i]);
}
for (const auto cur: toprocess) {
recompute(par[down[cur]], down[cur]);
}
auto upd = [&](ll i, ll we) {
ll cur = belong[i];
curw[cur] -= w[i];
w[i] = we;
curw[cur] += w[i];
// assert(par[down[cur]] != down[cur]);
recompute(par[down[cur]], down[cur]);
};
// F(i, 0, n-1) upd(i, weights[i]);
ll last = 0;
while (q--) {
G(d) G(e)
d = (d + last)%(n-1);
e = (e + last)%W;
upd(d, e);
last = all_answer.maximum();
cout << last << '\n';
}
}
