#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef __int128 lll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pld;
#define MAX 9223372036854775807LL
#define MIN -9223372036854775807LL
#define INF 0x3f3f3f3f3f3f3f3f
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << fixed; cout.precision(10);
#define sp << " "
#define en << "\n"
#define compress(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(), v.end()), v.end())
struct gujo
{
ll S, T, X, Y;
};
ll n, m, q;
ll all, bll;
pll edg[100010];
pll cost[100010];
vector<ll> vec[100010];
gujo qry[100010];
ll l[100010], r[100010], mid[100010];
ll IN[100010], OUT[100010], cc;
ll spa[100010][21], dep[100010];
ll ans[100010];
struct fenwicktree
{
ll bit[100010];
void init(void)
{
for(ll i = 1 ; i <= n ; i++)
bit[i] = 0;
}
void update(ll w, ll v)
{
for(ll i = w ; i <= n ; i += (i & (-i)))
bit[i] += v;
}
ll query(ll w)
{
ll ret = 0;
for(ll i = w ; i >= 1 ; i -= (i & (-i)))
ret += bit[i];
return ret;
}
}BIT;
void dfs0(ll here, ll pa)
{
IN[here] = ++cc;
spa[here][0] = pa;
dep[here] = dep[pa] + 1;
for(auto &i : vec[here])
{
if(i == pa)
continue;
dfs0(i, here);
}
OUT[here] = cc;
}
ll LCA(ll X, ll Y)
{
if(dep[X] < dep[Y])
swap(X, Y);
ll cha = dep[X] - dep[Y];
for(ll i = 20 ; i >= 0 ; i--)
{
if(cha >= (1LL << i))
{
cha -= (1LL << i);
X = spa[X][i];
}
}
if(X == Y)
return X;
for(ll i = 20 ; i >= 0 ; i--)
{
if(spa[X][i] != spa[Y][i])
{
X = spa[X][i];
Y = spa[Y][i];
}
}
return spa[X][0];
}
int main(void)
{
fastio
cin >> n >> m >> q;
for(ll i = 1 ; i < n ; i++)
{
cin >> all >> bll;
edg[i] = {all, bll};
vec[all].push_back(bll);
vec[bll].push_back(all);
}
for(ll i = 1 ; i <= m ; i++)
{
cin >> all >> bll;
cost[i] = {bll, all};
}
sort(cost + 1, cost + 1 + m);
for(ll i = 1 ; i <= q ; i++)
cin >> qry[i].S >> qry[i].T >> qry[i].X >> qry[i].Y;
dfs0(1, 0);
for(ll i = 1 ; i < n ; i++)
{
if(dep[edg[i].fi] < dep[edg[i].se])
swap(edg[i].fi, edg[i].se);
}
for(ll i = 1 ; i <= 20 ; i++)
{
for(ll j = 1 ; j <= n ; j++)
spa[j][i] = spa[spa[j][i - 1]][i - 1];
}
for(ll i = 1 ; i <= q ; i++)
l[i] = 1, r[i] = m;
for(ll o = 0 ; o <= 20 ; o++)
{
vector<pll> Q;
for(ll i = 1 ; i <= q ; i++)
{
mid[i] = (l[i] + r[i]) >> 1;
if(l[i] <= r[i])
Q.push_back({mid[i], i});
}
if(Q.empty())
break;
BIT.init();
sort(Q.begin(), Q.end());
ll p = 0;
for(ll i = 1 ; i <= m ; i++)
{
pll V = edg[cost[i].se];
BIT.update(IN[V.fi], cost[i].fi);
BIT.update(OUT[V.fi] + 1, -cost[i].fi);
while(p < (ll)Q.size() && Q[p].fi <= i)
{
ll num = Q[p].se;
ll gap = 0;
gap = BIT.query(IN[qry[num].S]) + BIT.query(IN[qry[num].T]) - 2 * BIT.query(IN[LCA(qry[num].S, qry[num].T)]);
if(gap > qry[num].Y)
r[num] = mid[num] - 1;
else
l[num] = mid[num] + 1;
p++;
}
}
}
vector<pll> Q;
for(ll i = 1 ; i <= q ; i++)
Q.push_back({r[i], i});
sort(Q.begin(), Q.end());
BIT.init();
ll p = 0;
while(p < (ll)Q.size() && Q[p].fi <= 0)
{
ll num = Q[p].se;
ll gap = 0;
ans[num] -= BIT.query(IN[qry[num].S]) + BIT.query(IN[qry[num].T]) - 2 * BIT.query(IN[LCA(qry[num].S, qry[num].T)]);
p++;
}
for(ll i = 1 ; i <= m ; i++)
{
pll V = edg[cost[i].se];
BIT.update(IN[V.fi], 1);
BIT.update(OUT[V.fi] + 1, -1);
while(p < (ll)Q.size() && Q[p].fi <= i)
{
ll num = Q[p].se;
ll gap = 0;
ans[num] -= BIT.query(IN[qry[num].S]) + BIT.query(IN[qry[num].T]) - 2 * BIT.query(IN[LCA(qry[num].S, qry[num].T)]);
p++;
}
}
for(ll i = 1 ; i <= q ; i++)
ans[i] += BIT.query(IN[qry[i].S]) + BIT.query(IN[qry[i].T]) - 2 * BIT.query(IN[LCA(qry[i].S, qry[i].T)]);
for(ll i = 1 ; i <= q ; i++)
{
if(ans[i] > qry[i].X)
cout << -1 en;
else
cout << qry[i].X - ans[i] en;
}
return 0;
}
