#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include<bits/stdc++.h>
using namespace std;
const int N=100'010,L=20;
vector<pair<int,int>> g[N];
int up[N][L];
int tin[N], tout[N],depth[N];
int tinn[N];
int tim=1;
void dfs(int at, int p) {
up[at][0]=p;
for(int i = 1;i<L;i++) {
up[at][i]=up[up[at][i-1]][i-1];
}
for(auto to:g[at]) {
if(to.first==p)continue;
tinn[to.first]=tim;
tin[to.second]=tim++;
depth[to.first]=depth[at]+1;
dfs(to.first,at);
tout[to.second]=tim++;
}
}
int lca(int a, int b) {
if(depth[a]<depth[b])swap(a,b);
int k=depth[a]-depth[b];
for(int i = L-1;i>=0;i--) {
if(k&(1<<i))a=up[a][i];
}
if(a==b)return a;
for(int j = L-1;j>=0;j--) {
if(up[a][j]!=up[b][j]) {
a=up[a][j];
b=up[b][j];
}
}
return up[a][0];
}
template<typename T>
struct BIT {
int N_;
vector<T> F_;
BIT(int n) {
N_=n;
F_=vector<T>(n+1);
}
void update(int at, T val) {
for(;at<=N_;at+=at&-at)F_[at]+=val;
}
T query(int l, int r) {
if(l!=1) {
return query(1,r)-query(1,l);
}
T res=0;
for(;r>0;r-=r&-r)res+=F_[r];
return res;
}
};
struct query {
int u, v, lc;
long long x,y;
};
signed main () {
cin.tie(0)->sync_with_stdio(0);
for(int i = 0;i<N;i++)
for(int j = 0;j<L;j++)
up[i][j]=1;
int n, m, q;
cin >> n >> m >> q;
for(int i = 0;i<n-1;i++) {
int a, b;
cin >> a >> b;
g[a].push_back({b,i});
g[b].push_back({a,i});
}
vector<pair<long long, int>> v(m);
for(int i = 0;i<m;i++) {
cin >> v[i].second >> v[i].first;
v[i].second--;
}
sort(v.begin(),v.end());
tinn[1]=tim++;
dfs(1,1);
query c[q];
for(int i=0;i<q;i++){
cin >> c[i].u >> c[i].v >> c[i].x >> c[i].y;
c[i].lc=lca(c[i].u,c[i].v);
}
int l[q], r[q],res[q];
for(int i = 0;i<q;i++) {
l[i]=0, r[i]=m;
res[i]=-1;
}
BIT<long long> b3(2*n+10);
for(int i = 0;i<m;i++) {
b3.update(tin[v[i].second],1);
b3.update(tout[v[i].second],-1);
}
while(1) {
vector<pair<int,int>> queries;
for(int i = 0;i<q;i++) {
if(l[i]>r[i])continue;
int tm=(l[i]+r[i])/2;
queries.push_back({tm,i});
}
if(queries.size()==0)break;
sort(queries.begin(),queries.end());
BIT<long long> b1(2*n+10),b2(2*n+10);
int pt=0;
for(int i = 0;i<queries.size();i++) {
while(pt<queries[i].first) {
b1.update(tin[v[pt].second],v[pt].first);
b1.update(tout[v[pt].second],-v[pt].first);
b2.update(tin[v[pt].second],1);
b2.update(tout[v[pt].second],-1);
pt++;
}
int j=queries[i].second;
int dst=b3.query(tinn[c[j].lc], tinn[c[j].u])+b3.query(tinn[c[j].lc],tinn[c[j].v]);
if(b1.query(tinn[c[j].lc],tinn[c[j].u])+b1.query(tinn[c[j].lc],tinn[c[j].v])<=c[j].y) {
l[j]=queries[i].first+1;
if(dst-(b2.query(tinn[c[j].lc],tinn[c[j].u])+b2.query(tinn[c[j].lc],tinn[c[j].v]))<=c[j].x) {
res[j]=c[j].x-(dst-(b2.query(tinn[c[j].lc],tinn[c[j].u])+b2.query(tinn[c[j].lc],tinn[c[j].v])));
}
}
else {
r[j]=queries[i].first-1;
}
}
}
for(int i = 0;i<q;i++) {
cout << res[i] << "\n";
}
return 0;
}
