/*Author: KawakiMeido*/
#include <bits/stdc++.h>
#define pb push_back
#define endl "\n"
#define ll long long
#define int long long
#define all(x) (x).begin(),(x).end()
#define pii pair<int,int>
#define fi first
#define se second
#define TEXT ""
using namespace std;
/*Constants*/
const int N = 2e5+10;
const int INF = 1e9+7;
const long long LLINF = 1e18+3;
/*Global Variables*/
int n,q,W;
vector<int> adj[N];
struct Node{
int ans,mxhi,mxlo,head,length;
Node(int _ans = 0, int _mxhi = 0, int _mxlo = 0, int _head = 0, int _length = 0){
ans = _ans;
mxhi = _mxhi;
mxlo = _mxlo;
head = _head;
length = _length;
}
void init(int _ans, int _mxhi, int _mxlo, int _head, int _length){
ans = _ans;
mxhi = _mxhi;
mxlo = _mxlo;
head = _head;
length = _length;
}
friend Node comb(Node l, Node r) {
if (l.ans == -1) return r;
if (r.ans == -1) return l;
Node i;
i.head = l.head;
i.length = l.length + r.head + r.length;
i.mxhi = max(l.mxhi, r.mxhi + r.head + l.length);
i.mxlo = max(r.mxlo, l.mxlo + r.head + r.length);
i.ans = max({l.ans, r.ans, l.mxlo + r.head + r.mxhi});
return i;
}
};
struct SegmentTree{
int n;
vector<Node> IT;
void update(int idx, int l, int r, int x, Node val){
if (r < x || x < l) return;
if (l==r){
IT[idx] = val;
return;
}
int mid = (l+r)/2;
update(idx*2,l,mid,x,val);
update(idx*2+1,mid+1,r,x,val);
IT[idx] = comb(IT[idx*2],IT[idx*2+1]);
}
Node get(int idx, int l, int r, int x, int y){
if (r < x || y < l) return Node(-1);
if (x <= l && r <= y) return IT[idx];
int mid = (l+r)/2;
return comb(
get(idx*2,l,mid,x,y),
get(idx*2+1,mid+1,r,x,y));
}
void Init(int _n){
n = _n;
IT.resize(4*n+10);
}
} ST;
//HLD
int curpos = 0;
int parent[N], sz[N], depth[N];
int root[N], pos[N];
int posmax[N];
set<pii,greater<pii>> mxlen[N], mxans[N];
pii smxlen[N], smxans[N];
void dfsHLD(int u, int p=0){
sz[u] = 1;
for (auto v:adj[u]){
if (v==p) continue;
parent[v] = u;
depth[v] = depth[u]+1;
dfsHLD(v,u);
sz[u] += sz[v];
}
}
void buildHLD(int u, int r){
pos[u] = ++curpos;
posmax[r] = pos[u];
root[u] = r;
int nxt = 0;
for (auto v:adj[u]){
if (v==parent[u]) continue;
if (!nxt || sz[v]>sz[nxt]) nxt = v;
}
if (nxt){
buildHLD(nxt,r);
}
for (auto v:adj[u]){
if (v==parent[u] || v==nxt) continue;
buildHLD(v,v);
}
}
void updateHLD(int x, int w){
// cout << "HLD: " << x << " " << w << endl;
Node tmp = ST.get(1,1,n,pos[x],pos[x]);
tmp.head = w;
ST.update(1,1,n,pos[x],tmp);
int u = x;
while (root[u]!=1){
// cout << u << ":" << endl;
tmp = ST.get(1,1,n,pos[root[u]],posmax[root[u]]);
int v = parent[root[u]];
mxlen[v].erase(smxlen[root[u]]);
mxans[v].erase(smxans[root[u]]);
smxlen[root[u]] = {tmp.mxhi+tmp.head,root[u]};
smxans[root[u]] = {tmp.ans,root[u]};
mxlen[v].insert(smxlen[root[u]]);
mxans[v].insert(smxans[root[u]]);
tmp = ST.get(1,1,n,pos[v],pos[v]);
int mx1 = 0, mx2 = 0, mxans1;
if (mxlen[v].size() >= 1) mx1 = (*mxlen[v].begin()).fi;
if (mxlen[v].size() >= 2) mx2 = (*(++mxlen[v].begin())).fi;
if (mxans[v].size() >= 1) mxans1 = (*mxans[v].begin()).fi;
// cout << mx1 << " " << mx2 << " " << mxans1 << endl;
tmp.mxlo = tmp.mxhi = mx1;
tmp.ans = max(mxans1,mx1+mx2);
ST.update(1,1,n,pos[v],tmp);
u = v;
}
}
int getHLD(){
Node tmp = ST.get(1,1,n,pos[1],posmax[1]);
return tmp.ans;
}
vector<pair<pii,int>> edge;
/*Solution*/
void solve(){
cin >> n >> q >> W;
for (int i=1; i<n; i++){
int u, v, w;
cin >> u >> v >> w;
adj[u].push_back(v);
adj[v].push_back(u);
edge.push_back({{u,v},w});
}
dfsHLD(1);
buildHLD(1,1);
ST.Init(n);
for (auto [uv,w]:edge){
auto [u,v] = uv;
if (pos[u] > pos[v]) updateHLD(u,w);
else updateHLD(v,w);
}
// for (int i=1; i<=n; i++){
// Node tmp = ST.get(1,1,n,pos[i],pos[i]);
// cout << tmp.ans << " " << tmp.head << " " << tmp.length << " " << tmp.mxhi << " " << tmp.mxlo << endl;
// }
int lastans = 0;
while (q--){
int id, w; cin >> id >> w;
id = (id+lastans)%(n-1);
w = (w+lastans)%W;
int u = edge[id].fi.fi;
int v = edge[id].fi.se;
if (pos[u] > pos[v]) updateHLD(u,w);
else updateHLD(v,w);
int ans = getHLD();
cout << ans << endl;
lastans = ans;
}
// for (int i=1; i<=n; i++){
// cout << i << " " << pos[i] << " " << root[i] << endl;
// }
}
/*Driver Code*/
signed main(){
cin.tie(0) -> sync_with_stdio(0);
if (fopen(TEXT".inp","r")){
freopen(TEXT".inp","r",stdin);
freopen(TEXT".out","w",stdout);
}
int testCount = 1;
// cin >> testCount;
while (testCount--){
solve();
}
return 0;
}
