#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define F first
#define S second
#define int long long
const int N = 1e5+5;
struct node{
int val, cnt, lc, rc;
};
node pers[50*N];
int tin[N], tout[N], h[N];
vector<pair<int, int>> cst;
vector<int> adj[N];
int timer=0;
int n, m, q;
vector<pair<int, int>> edges;
int p[N][18];
vector<int> roots;
int nodenum=0;
void dfs(int v, int par){
p[v][0]=par;
for(int i=1; i<18; i++){
p[v][i]=p[p[v][i-1]][i-1];
}
tin[v]=timer++;
h[v]=h[par]+1;
for(int to : adj[v]){
if(to!=par)dfs(to, v);
}
tout[v]=timer++;
}
void Build(int v, int l, int r){
if(l>r)return;
nodenum++;
if(l==r){
pers[v]={0, 0, -1, -1};
return;
}
int mid=l+r>>1;
if(l<=mid){
Build(2*v, l, mid);
pers[v].lc=2*v;
}
if(r>=mid+1){
Build(2*v+1, mid+1, r);
pers[v].rc=2*v+1;
}
}
void Update(int v, int l, int r, int ind, int val, int ps){
if(l==r){
pers[nodenum]={pers[v].val+val, pers[v].cnt+ps, -1, -1};
nodenum++;
return;
}
int mid=l+r>>1;
if(l<=ind && ind<=mid){
Update(pers[v].lc, l, mid, ind, val, ps);
int child=pers[v].rc;
pers[nodenum]={pers[child].val+pers[nodenum-1].val, pers[child].cnt+pers[nodenum-1].cnt, nodenum-1, child};
nodenum++;
}
if(mid+1<=ind && ind<=r){
Update(pers[v].rc, mid+1, r, ind, val, ps);
int child=pers[v].lc;
pers[nodenum]={pers[child].val+pers[nodenum-1].val, pers[child].cnt+pers[nodenum-1].cnt, child, nodenum-1};
nodenum++;
}
}
pair<int, int> Get(int v, int l, int r, int L, int R){
if(l>R || r<L)return {0, 0};
if(l>=L && r<=R)return {pers[v].val, pers[v].cnt};
int mid=l+r>>1;
pair<int, int> lft=Get(pers[v].lc, l, mid, L, R);
pair<int, int> rgt=Get(pers[v].rc, mid+1, r, L, R);
return {lft.F+rgt.F, lft.S+rgt.S};
}
bool anc(int u, int v){
if(tin[u]<=tin[v] && tout[u]>=tout[v])return 1;
return 0;
}
int lca(int u, int v){
if(anc(u, v))return u;
if(anc(v, u))return v;
for(int i=17; i>=0; i--){
if(!anc(p[u][i], v)){
u=p[u][i];
}
}
return p[u][0];
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> q;
for(int i=0; i<n-1; i++){
int a, b;
cin >> a >> b;
edges.pb({a, b});
adj[a].pb(b);
adj[b].pb(a);
}
dfs(1, 1);
for(auto & p : edges){
if(h[p.F]>h[p.S])swap(p.F, p.S);
}
for(int i=0; i<m; i++){
int ind, val;
cin >> ind >> val;
cst.pb({val, edges[ind-1].S});
}
sort(cst.begin(), cst.end());
roots.pb(0);
Build(0, 0, timer-1);
for(int i=0; i< m; i++){
Update(roots.back(), 0, timer-1, tin[cst[i].S], cst[i].F, 1);
roots.pb(nodenum-1);
Update(roots.back(), 0, timer-1, tout[cst[i].S], -cst[i].F, -1);
roots.pb(nodenum-1);
}
while(q--){
int a, b, x, y;
cin >> a >> b >> x >> y;
int lc=lca(a, b);
int dist=Get(roots.back(), 0, timer-1, 0, tin[a]).S+Get(roots.back(), 0, timer-1, 0, tin[b]).S-2*Get(roots.back(), 0, timer-1, 0, tin[lc]).S;
int l=0; int r=roots.size()/2;
int ans=1e9;
while(l<=r){
int s = l+r>>1;
int root=roots[2*s];
pair<int, int> lft=Get(root, 0, timer-1, 0, tin[a]);
pair<int, int> rgt=Get(root, 0, timer-1, 0, tin[b]);
pair<int, int> lcg=Get(root, 0, timer-1, 0, tin[lc]);
if(lft.F+rgt.F-2*lcg.F<=y){
l=s+1;
ans=dist-lft.S-rgt.S+2*lcg.S;
}
else r=s-1;
}
cout << max(-1ll, x-ans) << '\n';
}
}
