#include <bits/stdc++.h>
using namespace std;
#define int long long
//persistent segtree
struct segTree{
struct node{
int l,r,num,sum;
};
node *st;
node def;
int cr = 0;
segTree(int nodes){
st=new node[nodes];
def={-1,-1,0,0};
fill(st,st+nodes,def);
}
int cpy(int ind){
st[++cr]=st[ind];
return cr;
}
int update(int l, int r, int ind, int i, int val){
if(st[ind].l==-1){
st[ind].l=++cr;
}
if(st[ind].r==-1){
st[ind].r=++cr;
}
if(i<l||i>r){
return ind;
}
//okay must copy now
ind=cpy(ind);
if(l==r){
if(val<0){
st[ind].num--;
}
else{
st[ind].num++;
}
st[ind].sum+=val;
return ind;
}
int mid = (l+r)/2;
st[ind].l=update(l,mid,st[ind].l,i,val);
st[ind].r=update(mid+1,r,st[ind].r,i,val);
st[ind].num=st[st[ind].l].num+st[st[ind].r].num;
st[ind].sum=st[st[ind].l].sum+st[st[ind].r].sum;
return ind;
}
array<int,2> query(int l, int r, int s, int e, int ind){
if(st[ind].l==-1){
st[ind].l=++cr;
}
if(st[ind].r==-1){
st[ind].r=++cr;
}
if(e<l||s>r){
return {0,0};
}
if(s<=l&&r<=e){
return {st[ind].num,st[ind].sum};
}
int mid = (l+r)/2;
array<int,2>ans={0,0};
array<int,2>lef = query(l,mid,s,e,st[ind].l);
array<int,2>rig = query(mid+1,r,s,e,st[ind].r);
ans[0]=lef[0]+rig[0];
ans[1]=lef[1]+rig[1];
return ans;
}
};
const int lg = 20;
int tim=0;
void dfs(int st, vector<array<int,2>>g[], int p, int par[][lg], array<int,2>times[], int dep[], int d){
par[st][0]=p;
dep[st]=d;
for(int i = 1;i<lg;i++){
par[st][i]=par[par[st][i-1]][i-1];
}
times[st][0]=tim++;
for(array<int,2>e:g[st]){
if(e[0]==p)
continue;
dfs(e[0],g,st,par,times,dep,d+1);
}
times[st][1]=tim;
}
int lca(int x, int y, int par[][lg], int dep[]){
if(dep[x]<dep[y])
swap(x,y);
for(int i = lg-1;i>=0;i--){
if(dep[par[x][i]]>=dep[y]){
x=par[x][i];
}
}
//at same depth now
for(int i = lg-1;i>=0;i--){
if(par[x][i]!=par[y][i]){
x=par[x][i];
y=par[y][i];
}
}
if(x==y){
return x;
}
return par[x][0];
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,m,q;
cin >> n >> m >> q;
vector<array<int,2>>g[n];
array<int,2>edges[n-1];
for(int i = 0;i<n-1;i++){
int a,b;
cin >> a >> b;
a--;b--;
g[a].push_back({b,i});
g[b].push_back({a,i});
edges[i]={a,b};
}
int par[n][20];
int dep[n];
array<int,2>times[n];
dfs(0,g,0,par,times,dep,0);
array<int,2>costs[m];
for(int i = 0;i<m;i++){
int p,c;
cin >> p >> c;
p--;
int a,b;
a=edges[p][0];
b=edges[p][1];
if(dep[a]>dep[b])
costs[i]={c,a};
else{
costs[i]={c,b};
}
}
sort(costs,costs+m);
segTree per(1e6);
vector<int>segs;
segs.push_back(0);
//TODO: maybe add build for memory optimisation in segtree
int las = 0;
for(array<int,2>check:costs){
las=per.update(0,n,las,times[check[1]][0],check[0]);
segs.push_back(per.update(0,n,las,times[check[1]][1],-check[0]));
las=segs.back();
}
while(q--){
int s,t,x,y;
cin >> s >> t >> x >> y;
s--;t--;
//x is gold, y is silver
int lc = lca(s,t,par,dep);
int tot = per.query(0,n,0,times[s][0],las)[0]+per.query(0,n,0,times[t][0],las)[0]-2*per.query(0,n,0,times[lc][0],las)[0];
x-=tot;
int lo = 0;
int hi = m;
while(lo<hi){
int mid = (lo+hi+1)/2;
int ind = segs[mid];
int sum = per.query(0,n,0,times[s][0],ind)[1]+per.query(0,n,0,times[t][0],ind)[1]-2*per.query(0,n,0,times[lc][0],ind)[1];
if(sum<=y){
lo=mid;
}
else{
hi=mid-1;
}
}
lo=segs[lo];
int did = per.query(0,n,0,times[s][0],lo)[0]+per.query(0,n,0,times[t][0],lo)[0]-2*per.query(0,n,0,times[lc][0],lo)[0];
x+=did;
if(x<0){
cout << -1 << "\n";
}
else{
cout << x << "\n";
}
}
return 0;
}
