#include <bits/stdc++.h>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
#pragma GCC optimize("Ofast")
#define int ll
using namespace std;
typedef long long ll;
typedef pair <ll, ll> pii;
const ll NMAX = 100002;
const ll INF = (1LL << 58);
const ll nrbits = 18;
const ll MOD = 998244353;
vector <pii> v[NMAX];
vector <int> children[NMAX];
int n;
pii timp[NMAX * nrbits];
struct edge {
int a, b;
ll c;
} edges[NMAX];
class AINT {
public:
struct Node {
ll mx, lazy;
};
Node* aint;
int n;
void init(int _n) {
n = _n;
aint = new Node[4 * (n + 1)];
for(int i = 0; i < 4 * (n + 1); i++) {
aint[i].mx = 0;
aint[i].lazy = 0;
}
}
Node combine(Node a, Node b) {
Node sol = {0, 0};
sol.mx = max(a.mx, b.mx);
return sol;
}
void propaga(int node, int st, int dr) {
if(st != dr) {
aint[node * 2].lazy += aint[node].lazy;
aint[node * 2 + 1].lazy += aint[node].lazy;
}
aint[node].mx += aint[node].lazy;
aint[node].lazy = 0;
}
void baga(int node, int st, int dr, int a, int b, int val) {
propaga(node, st, dr);
if(a <= st && dr <= b) {
aint[node].lazy += val;
return;
}
int mid = (st + dr) / 2;
if(a <= mid) {
baga(node * 2, st, mid, a, b, val);
}
if(b > mid) {
baga(node * 2 + 1, mid + 1, dr, a, b, val);
}
propaga(node * 2, st, mid);
propaga(node * 2 + 1, mid + 1, dr);
aint[node] = combine(aint[node * 2], aint[node * 2 + 1]);
}
ll sol(int node, int st, int dr, int a, int b){
propaga(node, st, dr);
if(a <= st && dr <= b){
return aint[node].mx;
}
int mid = (st + dr) / 2;
ll maxim = 0;
if(a <= mid)
maxim = max(maxim, sol(node * 2, st, mid, a, b));
if(b > mid)
maxim = max(maxim, sol(node * 2 + 1, mid + 1, dr, a, b));
return maxim;
}
void update(int st, int dr, int val) {
baga(1, 1, n, st, dr, val);
}
ll query(int st, int dr) {
return sol(1, 1, n, st, dr);
}
} st[NMAX];
int viz[NMAX];
int stamp;
struct event {
int st, dr, unde, subarb;
};
vector <event> events[NMAX];
multiset <ll> candidates;
multiset <ll> indv[NMAX];
int sz[NMAX];
int total;
void getsz(int node, int p) {
sz[node] = 1;
for(auto x : v[node]) {
if(x.first == p || viz[x.first]) continue;
getsz(x.first, node);
sz[node] += sz[x.first];
}
total = sz[node];
}
int findCentroid(int node, int p) {
for(auto x : v[node]) {
if(x.first == p || viz[x.first]) continue;
if(sz[x.first] > total / 2)
return findCentroid(x.first, node);
}
return node;
}
int unde;
int subarb;
void DFS(int node, int p) {
stamp++;
if(timp[subarb].first == 0) timp[subarb].first = stamp;
timp[subarb].second = stamp;
for(auto x : v[node]) {
if(x.first == p || viz[x.first]) continue;
event nou = {stamp + 1, 0, unde, subarb};
DFS(x.first, node);
nou.dr = stamp;
events[x.second].push_back(nou);
}
}
int cnt = 0;
void centroid(int node) {
getsz(node, 0);
int C = findCentroid(node, 0);
st[C].init(total);
viz[C] = 1;
stamp = 1; /// n-are logica tbh
unde = C;
for(auto x : v[C]){
if(viz[x.first]) continue;
children[C].push_back(++cnt);
subarb = cnt;
event nou = {stamp + 1, 0, unde, subarb};
DFS(x.first, C);
nou.dr = stamp;
events[x.second].push_back(nou);
}
for(auto x : v[C]) {
if(viz[x.first]) continue;
centroid(x.first);
}
}
ll compute(int i){
if(indv[i].size() == 0)
return 0;
if(indv[i].size() == 1)
return *indv[i].begin();
auto it =indv[i].end();
return (*prev(it) + *prev(prev(it)));
}
signed main() {
#ifdef HOME
ifstream cin(".in");
ofstream cout(".out");
#endif // HOME
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int q, w, i;
cin >> n >> q >> w;
for(i = 1; i < n; i++) {
int a, b;
ll c;
cin >> a >> b >> c;
v[a].push_back({b, i});
v[b].push_back({a, i});
edges[i] = {a, b, c};
}
centroid(1);
for(int a = 1; a < n; a++) {
for(auto x : events[a]) {
st[x.unde].update(x.st, x.dr, edges[a].c);
}
}
for(i = 1; i <= n; i++){
//debug(i);
for(auto x : children[i]){
//debug(st[i].query(timp[x].first, timp[x].second));
indv[i].insert(st[i].query(timp[x].first, timp[x].second));
}
candidates.insert(compute(i));
}
ll last = 0;
for(i = 1; i <= q; i++) {
ll a, b;
cin >> a >> b;
a += last;
a %= (n - 1);
b += last;
b %= w;
a++;
int toAdd = b - edges[a].c;
edges[a].c = b;
for(auto x : events[a]) {
candidates.erase(candidates.find(compute(x.unde)));
indv[x.unde].erase(indv[x.unde].find(st[x.unde].query(timp[x.subarb].first, timp[x.subarb].second)));
st[x.unde].update(x.st, x.dr, toAdd);
indv[x.unde].insert(st[x.unde].query(timp[x.subarb].first, timp[x.subarb].second));
candidates.insert(compute(x.unde));
}
cout << *prev(candidates.end()) << '\n';
last = *prev(candidates.end());
}
return 0;
}
