#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt(x) __builtin_popcount(x)
#define pb push_back
#define popf pop_front
#define popb pop_back
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
fastIO();
if (str != "") {
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 3e5 + 10, LOG = 21;
vector<pair<long long, long long>> adj[N];
long long n, q, w, cost[N], which[N];
long long p[N], first[N], last[N];
int op[N];
vector<int> path;
void dfs(int node, int parent) {
for(auto i: adj[node]) {
if(i.first == parent) continue;
path.push_back(i.second);
dfs(i.first, node);
path.push_back(i.second);
}
}
struct segTree {
struct node {
long long value, max_abc, max_a, max_bc, max_ab, max_b;
};
long long size = 1;
vector<node> tree;
void init(long long s) {
while(size < s) {
size *= 2;
}
tree.assign(2 * size - 1, {0, 0, 0, 0, 0, 0});
}
node lef(long long val) {
return {val, val, val, val, 0, 0};
}
node rig(long long val) {
return {-val, val, 0, val, val, 2 * val};
}
node merge(node a, node b) {
a.max_abc = max({a.max_abc, b.max_abc, a.max_ab + b.max_a + a.value, a.max_a + b.max_bc - a.value});
a.max_ab = max({a.max_ab, b.max_ab - a.value, a.max_a + b.max_b - 2 * a.value});
a.max_bc = max({a.max_bc, b.max_bc - a.value, a.max_b + b.max_a + a.value});
a.max_a = max({a.max_a, b.max_a + a.value});
a.max_b = max(a.max_b, b.max_b - 2 * a.value);
a.value = a.value + b.value;
return a;
}
void upd(int u, int x, int lx, int rx) {
if(rx - lx == 1) {
long long cur = cost[path[lx - 1]];
if(op[lx]) {
tree[x] = lef(cur);
} else {
tree[x] = rig(cur);
}
} else {
int mid = (lx + rx) / 2;
if(u < mid) {
upd(u, 2 * x + 1, lx, mid);
} else {
upd(u, 2 * x + 2, mid, rx);
}
tree[x] = merge(tree[2 * x + 1], tree[2 * x + 2]);
}
}
void upd(int u) {
upd(u, 0, 0, size);
}
node qry(int l, int r, int x, int lx, int rx) {
if(lx >= r || rx <= l) {
return {0, 0, 0, 0, 0, 0};
}
if(lx >= l && rx <= r) {
return tree[x];
}
int mid = (lx + rx) / 2;
node s1 = qry(l, r, 2 * x + 1, lx, mid);
node s2 = qry(l, r, 2 * x + 2, mid, rx);
return merge(s1, s2);
}
node qry(int l, int r) {
return qry(l, r, 0, 0, size);
}
};
segTree seg;
void solve_() {
cin >> n >> q >> w;
seg.init(2 * n + 10);
for(int i = 1; i <= n - 1; i++) {
long long a, b, c; cin >> a >> b >> c;
if(a > b) swap(a, b);
adj[a].push_back({b, i});
adj[b].push_back({a, i});
//
cost[i] = c;
which[i] = b;
}
dfs(1, 0);
memset(first, -1, sizeof(first));
memset(last, -1, sizeof(last));
for(int i = 0; i < sz(path); i++) {
if(first[path[i]] == -1) {
first[path[i]] = (i + 1);
op[i + 1] = 1;
}
last[path[i]] = (i + 1);
}
for(int i = 1; i <= sz(path); i++) {
seg.upd(i);
}
long long las = 0;
while(q--) {
long long d, e; cin >> d >> e;
d = (d + las) % (n - 1);
e = (e + las) % w;
d++;
cost[d] = e;
seg.upd(first[d]);
seg.upd(last[d]);
cout << seg.tree[0].max_abc << '\n';
las = seg.tree[0].max_abc;
}
}
int main() {
setIO();
auto solve = [&](int test_case)-> void {
while(test_case--) {
solve_();
}
};
int test_cases = 1;
// cin >> test_cases;
solve(test_cases);
return 0;
}
