#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());
/*
Competitive Programming notes that I need to study & fix my dumbass self:
1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops, I don't know
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you
2. Stress:
- Don't be cocky and think stressing with your dumbass brute-force solution will give you guaranteed AC. 
- Always try generating big testcases and try if they run
3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time
I hate offline because I am dumb
*/
typedef pair<int, int> ii;
const int N = 1e5+5;
const int M = 17;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 
// Fenwick 
int bit[N];
void upd(int i, int v) 
{
	for (; i < N; i += i & -i) bit[i] += v;
}
int get(int i) 
{
	int ret = 0;
	for (; i; i -= i & -i) ret += bit[i];
	return ret;
}
int query(int l, int r) 
{
	return get(r) - get(l-1);
}
int n,m,q;
vector<int> adj[N], cand[N];
vector<ii> c, e;
int s[N], t[N], x[N], y[N], l[N], r[N], mid[N], cost[N];
// HLD + binlift
int sz[N], h[N], par[N], tin[N], tout[N], heavy[N], head[N], up[N][M], tot[N];
int timer = 0;
void predfs(int u, int p) 
{
	sz[u] = 1;
	up[u][0] = par[u] = p;
	for (int i = 1; i < M; i++) up[u][i] = up[up[u][i-1]][i-1];
	for (auto v : adj[u]) 
	{
		if (v == p) continue;
		h[v] = h[u] + 1;
		predfs(v,u);
		sz[u] += sz[v];
		if (sz[heavy[u]] < sz[v]) heavy[u] = v;
	}
}
void decompose(int u, int p) 
{
	tin[u] = ++timer, head[u] = p;
	if (heavy[u]) 
	{
		decompose(heavy[u], p);
	}
	for (auto v : adj[u]) 
	{
		if (v == par[u] || v == heavy[u]) continue;
		decompose(v,v);
	}
	tout[u] = timer;
}
 
int lca(int u,int v) 
{
	if (h[u] < h[v]) swap(u,v);
	int diff = h[u]-h[v];
	for (int i=0;i<M;i++) 
	{
		if (diff >> i & 1) u = up[u][i];
	}
	if (u==v) return u;
	for (int i=M-1;i>=0;i--) 
	{
		if (up[u][i] != up[v][i]) u = up[u][i], v = up[v][i];
	}
	return up[u][0];
}
int sumpath(int a, int b) 
{
	int res = 0;
	for (; head[a] != head[b]; b = par[head[b]]) 
	{
		if (h[head[a]] > h[head[b]]) swap(a,b);
		res += query(tin[head[b]], tin[b]);
	}
	if (h[a] > h[b]) swap(a,b);
	res += query(tin[a], tin[b]);
	return res - cost[a];
}
int dist(int u, int v) 
{
	return tot[u] + tot[v] - 2 * tot[lca(u,v)];
}
void dfscost(int u, int p) 
{
	for (auto v : adj[u]) 
	{
		if (v == p) continue;
		tot[v] = tot[u] + cost[v];
		dfscost(v,u);
	}
}
void solve()
{
	cin>>n>>m>>q;
	for (int i = 1; i < n; i++) 
	{
		int u,v; cin>>u>>v;
		adj[u].pb(v); adj[v].pb(u);
		e.pb({u,v});
	}
	predfs(1,1);
	decompose(1,1);
	c.pb({0,0});
	for (int i = 0; i < m; i++) 
	{
		int p, cc; cin>>p>>cc; --p;
		int u = e[p].fi, v = e[p].se;
		if (h[u] < h[v]) c.pb({cc, v}), cost[v]++;
		else c.pb({cc, u}), cost[u]++;
	}
	sort(all(c));
	dfscost(1,1);
	// for (auto i : c) cout<<i.se<<" "<<i.fi<<endl;
	// cout<<endl;
	for (int i = 0; i < q; i++) 
	{
		cin>>s[i]>>t[i]>>x[i]>>y[i];
		l[i] = 0, r[i] = m;
	}
	while (true) {
		bool check = 0;
		for (int i = 0; i < q; i++) 
		{
			if (l[i] >= r[i]) continue;
			check = 1;
			mid[i] = (l[i] + r[i] + 1) >> 1;
			cand[mid[i]].pb(i);
		}
		if (!check) break;
		// for (int i = 0; i < q; i++) cout<<l[i]<<" "<<r[i]<<endl;
		for (int i = 1; i <= n; i++) bit[i] = 0, cost[i] = 0;
		for (int i = 0; i <= m; i++) 
		{
			// cout<<i<<endl;
			if (i) 
			{
				// cout<<c[i].se<<" "<<c[i].fi<<endl;
				upd(tin[c[i].se], c[i].fi);
				cost[c[i].se] += c[i].fi;
			}
			for (auto j : cand[i]) 
			{
				int sum = sumpath(s[j], t[j]);
				// cout<<s[j]<<" "<<t[j]<<" "<<sum<<endl;
				if (sum <= y[j]) l[j] = mid[j];
				else r[j] = mid[j]-1;
			}
			// cout<<endl;
			cand[i].clear();
		}
		// break;
	}
	// for (int i = 0; i < q; i++) cout<<l[i]<<" ";
	// cout<<endl;
	vector<int> ans(q);
	for (int i = 0; i < q; i++) cand[l[i]].pb(i);
	for (int i = 1; i <= n; i++) bit[i] = 0, cost[i] = 0;
	for (int i = 0; i <= m; i++) 
	{
		if (i) 
		{
			// cout<<c[i].se<<" "<<c[i].fi<<endl;
			upd(tin[c[i].se], 1);
			cost[c[i].se]++;
		}	
		for (auto j : cand[i]) 
		{
			int gold = dist(s[j], t[j]) - sumpath(s[j], t[j]);
			// cout<<s[j]<<" "<<t[j]<<" "<<dist(s[j], t[j])<<" "<<sumpath(s[j], t[j])<<endl;
			if (gold > x[j]) ans[j] = -1;
			else ans[j] = x[j] - gold;
		}
	}
	for (int i = 0; i < q; i++) cout<<ans[i]<<endl;
}
/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/
signed main()
{
	bruh
	//freopen("input.inp","r",stdin);
	//freopen("output.inp","w",stdout);
	solve();
}
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