#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define f first
#define int long long
#define s second
#define pii pair<int,int>
template<class T>bool umax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>bool umin(T &a,T b){if(b<a){a=b;return true;}return false;}
typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
tree_order_statistics_node_update> ordered_set;
const int N = 1e6 + 5;
const int inf = 1e17 + 7;
const int mod = 1e9 + 7;
int n,m,k;
vector<tuple<int,int,int>>g[N];
vector<int>edge;
struct st{
int pref,suff,sum,ans,all,usuff,upref;
};
st t[N*4];
pii p[N*4];
void dfs(int x, int pr){
for(auto [to,w,ind] : g[x]){
if(to == pr)continue;
edge.pb(w);
p[ind].f = edge.size();
dfs(to,x);
edge.pb(-w);
p[ind].s = edge.size();
}
}
void merge(int ind){
#define seg t
#define allans all
#define prefans upref
#define suffans usuff
seg[ind].pref=max(seg[2*ind].pref, seg[2*ind].sum+seg[2*ind+1].pref);
seg[ind].suff=max(seg[2*ind+1].suff, -seg[2*ind+1].sum+seg[2*ind].suff);
seg[ind].sum=seg[2*ind].sum+seg[2*ind+1].sum;
seg[ind].allans=max(seg[2*ind].allans+seg[2*ind+1].sum, -seg[2*ind].sum+seg[2*ind+1].allans);
seg[ind].prefans=max({seg[2*ind].prefans, seg[2*ind].allans+seg[2*ind+1].pref, -seg[2*ind].sum+seg[2*ind+1].prefans});
seg[ind].suffans=max({seg[2*ind+1].suffans, seg[2*ind+1].allans+seg[2*ind].suff, seg[2*ind+1].sum+seg[2*ind].suffans});
seg[ind].ans=max({seg[2*ind].ans, seg[2*ind+1].ans, seg[2*ind].suffans+seg[2*ind+1].pref, seg[2*ind].suff+seg[2*ind+1].prefans});
}
void build(int l, int r, int ind){
if(r==l){
t[ind].pref=max(0LL, edge[l-1]);
t[ind].suff=max(0LL, -edge[l-1]);
t[ind].ans=t[ind].upref=t[ind].usuff=t[ind].all=abs(edge[l-1]);
t[ind].sum=edge[l-1];
}
else{
int mid=(r+l)>>1;
build(l, mid, 2*ind); build(mid+1, r, 2*ind+1);
merge(ind);
}/*
cout << ind << "\n";
cout<<seg[ind].pref<<"\n"<<seg[ind].suff<<"\n"<<seg[ind].sum<<"\n"<<seg[ind].allans<<"\n"<<seg[ind].prefans<<"\n"<<seg[ind].suffans<<"\n"<<seg[ind].ans<<"\n";
cout << "\n";*/
}
void update(int tl, int tr, int v, int pos, int val){
if(tl == tr){
t[v].pref = max(0ll, val);
t[v].suff = max(0ll, -val);
t[v].sum = val;
t[v].all = abs(val);
t[v].upref = abs(val);
t[v].usuff = abs(val);
t[v].ans = abs(val);
return;
}
int tm = (tl+tr)/2;
if(pos <= tm){
update(tl,tm,v*2,pos,val);
}
else update(tm+1,tr,v*2+1,pos,val);
merge(v);
}
void solve(){
cin >> n >> m >> k;
for(int i = 1;i<n;i++){
int a,b,c;
cin >> a >> b >> c;
g[a].pb({b,c,i-1});
g[b].pb({a,c,i-1});
}
dfs(1,-1);
build(1,edge.size(),1);
/* int ind = 1;
cout << t[ind].pref<<"\n" << t[ind].suff<<"\n" << t[ind].sum<<"\n" << t[ind].all<<"\n" << t[ind].upref<<"\n" << t[ind].usuff<<"\n" << t[ind].ans<<"\n";*/
//etu huyni ya daje ne sam zakonchil, pizdec, chas nochi, poydu podrochu
int last = 0;
while(m--){
int a,b;
cin >> a >> b;
a = (a+last)%(n-1);
b = (b+last)%k;
update(1,edge.size(),1,p[a].f,b);
update(1,edge.size(),1,p[a].s,-b);
//~ cout << p[a].f<<" "<<p[a].s<<"\n";
cout << t[1].ans<<"\n";
last = t[1].ans;
}
}
/*
// Success consists of going from failure to failure without loss of enthusiasm
// Problems means that you are trying
// Soberis dolboyeb
*/
signed main()
{
// freopen("seq.in", "r", stdin);
// freopen("seq.out", "w", stdout);
ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
int tt=1;//cin>>tt;
while(tt--)solve();
}
