///TRAN THAI BAO :3
#include <iostream>
#include <cstdio>
#include <map>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;
#define maxN 100007
#define oo 1000000000000000000
#define MAXVAL 1000000000
typedef pair<long long, long long> pii;
pii eList[maxN];
vector<pii>station;
int n, p, q;
int up[maxN][20];
long long gold[maxN];
struct QUERY
{
int lo, hi, mid;
int s, t, lca;
long long si;
int id;
};
bool CMPQUERY(QUERY one, QUERY two)
{
if(one.mid != two.mid)
return one.mid < two.mid;
return one.id < two.id;
}
vector<QUERY>curQ;
struct BIT
{
long long b1[maxN];
long long b2[maxN];
void reset()
{
memset(b1, 0, sizeof(b1));
memset(b2, 0, sizeof(b2));
}
void update(long long b[], int pos, long long val)
{
while(pos <= n)
{
b[pos] += val;
pos += (pos & -pos);
}
}
long long get(long long b[], int pos)
{
long long ans = 0;
for(; pos > 0; pos -= (pos & -pos))
ans += b[pos];
return ans;
}
void updRange(int l, int r, long long val)
{
update(b1, l, val*(n-l+1));
update(b1, r+1, -val*(n-r));
update(b2, l, val);
update(b2, r+1, -val);
}
long long pref(int pos)
{
return get(b1, pos) - get(b2, pos)*(n-pos);
}
long long range(int l, int r)
{
return pref(r) - pref(l-1);
}
};
vector<int>adj[maxN];
int in[maxN] = {0};
int ou[maxN] = {0};
int h[maxN] = {0};
int curT = 0;
long long ans[maxN];
BIT bit3;
BIT bit1, bit2;
void dfs(int u, int p)
{
h[u] = h[p]+1;
up[u][0] = p;
in[u] = ++curT;
int v;
for(int i = 0; i < adj[u].size(); i++)
{
v = adj[u][i];
if(v == p)
continue;
dfs(v, u);
}
ou[u] = curT;
}
int LCA(int u, int v)
{
if(h[u] < h[v]) swap(u, v);
int d = h[u] - h[v];
for(int i = 0; i < 20; i++)
if((d >> i) & 1)
u = up[u][i];
if(u == v)
return u;
for(int i = 19; i >= 0; i--)
if(up[u][i] != up[v][i])
{
u = up[u][i];
v = up[v][i];
}
return up[u][0];
}
void readData()
{
int u, v, w;
cin >> n >> p >> q;
for(int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
eList[i] = {u, v};
}
dfs(1, 1);
for(int i = 1; i < 20; i++)
for(int j = 1; j <= n; j++)
up[j][i] = up[up[j][i-1]][i-1];
for(int i = 0; i < p; i++)
{
cin >> u >> w;
v = eList[u].second;
u = eList[u].first;
if(up[u][0] != v)
swap(u, v);
station.push_back({w, u});
}
long long s, t, x, y;
for(int i = 1; i <= q; i++)
{
ans[i] = oo;
cin >> s >> t >> x >> y;
gold[i] = x;
QUERY tmp = {0, p, p/2, s, t, LCA(s, t), y, i};
curQ.push_back(tmp);
}
sort(station.begin(), station.end());
for(int i = 0; i < station.size(); i++)
{
u = station[i].second;
bit3.updRange(in[u], ou[u], 1);
}
}
void compute()
{
int u, v, w;
vector<QUERY>nxt;
bit1.reset();
for(int i = 0; i <= n; i++)
{
bit2.b1[i] = bit3.b1[i];
bit2.b2[i] = bit3.b2[i];
}
sort(curQ.begin(), curQ.end(), CMPQUERY);
int j = 0;
for(int i = 0; i < curQ.size(); i++)
{
QUERY cur = curQ[i];
while(j < cur.mid)
{
w = station[j].first;
u = station[j].second;
bit1.updRange(in[u], ou[u], w);
bit2.updRange(in[u], ou[u], -1);
j++;
}
long long curCost = bit1.range(in[cur.s], in[cur.s]) + bit1.range(in[cur.t], in[cur.t]) - 2ll*bit1.range(in[cur.lca], in[cur.lca]);
if(curCost <= cur.si)
{
long long curAns = bit2.range(in[cur.s], in[cur.s]) + bit2.range(in[cur.t], in[cur.t]) - 2ll*bit2.range(in[cur.lca], in[cur.lca]);
ans[cur.id] = min(ans[cur.id], curAns);
cur.lo = cur.mid+1;
cur.mid = (cur.lo + cur.hi)/2;
}
else
{
cur.hi = cur.mid-1;
cur.mid = (cur.lo + cur.hi)/2;
}
if(cur.lo <= cur.hi)
nxt.push_back(cur);
}
curQ.clear();
swap(nxt, curQ);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
readData();
while(!curQ.empty())
compute();
for(int i = 1; i <= q; i++)
if(ans[i] <= gold[i])
cout << gold[i] - ans[i] << "\n";
else cout << "-1\n";
return 0;
}
