#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define F0R(i, x) FOR(i, 0, x)
#define FORd(i, a, b) for(int i = (b)-1; i >= (a); i--)
#define F0Rd(i, x) FORd(i, 0, x)
const int MAX_N = 20;
const ll INF = 1e18;
int n, m, q, t, cnt;
int dep[MAX_N], anc[MAX_N][20], rt[MAX_N], ch[50*MAX_N][2];
ll sm[50*MAX_N], num[50*MAX_N];
vector<ll> nums[MAX_N];
vector<pii> adj[MAX_N];
int upd(int x, ll v, ll l = 0, ll r = 1e9){
ll x2 = ++cnt, m = (l+r)/2ll;
if(l == r){
sm[x2] = sm[x]+v;
num[x2] = num[x]+1;
return x2;
}
if(v <= m){
ch[x2][0] = upd(ch[x][0], v, l, m);
ch[x2][1] = ch[x][1];
} else{
ch[x2][0] = ch[x][0];
ch[x2][1] = upd(ch[x][1], v, m+1ll, r);
}
sm[x2] = sm[ch[x2][0]]+sm[ch[x2][1]];
num[x2] = num[ch[x2][0]]+num[ch[x2][1]];
return x2;
}
ll qry1(int x, ll ql, ll qr, ll l = 0, ll r = 1e9){
if(!x || ql > r || qr < l) return 0;
if(ql <= l && qr >= r) return sm[x];
ll m = (l+r)/2ll;
return qry1(ch[x][0], ql, qr, l, m)+qry1(ch[x][1], ql, qr, m+1, r);
}
ll qry2(int x, ll ql, ll qr, ll l = 0, ll r = 1e9){
if(!x || ql > r || qr < l) return 0;
if(ql <= l && qr >= r) return num[x];
ll m = (l+r)/2ll;
return qry2(ch[x][0], ql, qr, l, m)+qry2(ch[x][1], ql, qr, m+1, r);
}
void dfs(int curr, int par){
for(auto x : adj[curr]){
if(x.ff == par) continue;
dep[x.ff] = dep[curr]+1;
anc[x.ff][0] = curr;
rt[x.ff] = rt[curr];
for(auto y : nums[x.ss])
rt[x.ff] = upd(rt[x.ff], y);
dfs(x.ff, curr);
}
}
int lca(int a, int b){
if(dep[a] > dep[b]) swap(a, b);
F0Rd(i, 20) if(dep[a]+(1 << i) <= dep[b])
b = anc[b][i];
if(a == b) return a;
F0Rd(i, 20) if(anc[a][i] != anc[b][i])
a = anc[a][i], b = anc[b][i];
return anc[a][0];
}
pair<pii, ll> solve(int a, int b, ll x){ // number of things > x, number of things = x, sum of things < x
int c = lca(a, b);
pii y = {qry2(rt[a], x+1, 1e9)+qry2(rt[b], x+1, 1e9)-2ll*qry2(rt[c], x+1, 1e9), qry2(rt[a], x, x)+qry2(rt[b], x, x)-2ll*qry2(rt[c], x, x)};
return {y, qry1(rt[a], 0, x-1)+qry1(rt[b], 0, x-1)-2ll*qry1(rt[c], 0, x-1)};
}
int main(int argc, const char * argv[]){
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);
cin >> n >> m >> q;
F0R(i, n-1){
int a, b; cin >> a >> b; a--, b--;
adj[a].push_back({b, i});
adj[b].push_back({a, i});
}
F0R(i, m){
int a, b; cin >> a >> b; a--;
nums[a].push_back(b);
}
dfs(0, -1);
FOR(x, 1, 20) F0R(i, n)
anc[i][x] = anc[anc[i][x-1]][x-1];
F0R(i, q){
ll s, t, x, y; cin >> s >> t >> x >> y; s--, t--;
ll l = 0, r = min(y+1ll, (ll) 1e9);
while(l+1 < r){
ll mid = (l+r)/2ll;
if(solve(s, t, mid).ss <= y) l = mid;
else r = mid;
}
pair<pll, ll> z = solve(s, t, l);
ll ans = z.ff.ff+max(z.ff.ss-(y-z.ss)/l, 0ll);
if(ans > x) cout << "-1\n";
else cout << x-ans << '\n';
}
return 0;
}
