#include <iostream>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <deque>
#include <stack>
#include <queue>
#include <algorithm>
#include <cassert>
#include <math.h>
#define int long long
#define ii pair<int,int>
#define fi first
#define se second
#define getbit(x,y) (((x)>>(y))&1)
#define turnon(x,y) ((x)|(1<<y))
#define turnof(x,y) ((x)^(1<<y))
#define oo 1000000000000000000
#define pb push_back
#define all(x) x.begin(),x.end()
#define con(mask) mask=(mask-1)&mask
#define Unique(val) val.erase(unique(val.begin(),val.end()),val.end())
const int mod = 1e9 + 7;
const int base = 1e9;
using namespace std;
vector<int>e[100005];
int cnt_silver[100005], cnt_gold[100005];
int n, q, m;
struct nhan {
int u, v, gold, silver;
nhan (int _u = 0, int _v = 0, int _gold = 0, int _silver = 0) {
u = _u;
v = _v;
gold = _gold;
silver = _silver;
}
} h[100005];
int L[100005], R[100005];
ii Edge[100005];
vector<ii>a;
int f[100005][17];
int hi[100005];
int tin[100005], tout[100005], cnt;
void dfs(int u, int p) {
tin[u] = ++cnt;
for(int i = 0; i < e[u].size(); i++) {
int v = e[u][i];
if(v != p) {
hi[v] = hi[u] + 1;
f[v][0] = u;
dfs(v, u);
}
}
tout[u] = cnt;
}
int lca(int u, int v) {
if(hi[u] > hi[v]) swap(u, v);
for(int i = 16; i >= 0; i--) {
if(hi[f[v][i]] >= hi[u]) {
v = f[v][i];
}
}
if(u == v) return u;
for(int i = 16; i >= 0; i--) {
if(f[u][i] != f[v][i]) {
u = f[u][i];
v = f[v][i];
}
}
return f[u][0];
}
int bit[100005];
int bit_canh[100005];
void update(int a[], int pos, int val) {
for(int i = pos; i <= n; i += i&-i) {
a[i] += val;
}
}
int get(int a[], int pos) {
int ans = 0;
for(int i = pos; i >= 1; i -= i&-i) {
ans += a[i];
}
return ans;
}
int need[100005];
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
for(int i = 1; i < n; i++) {
int u, v, w;
cin >> u >> v;
e[u].pb(v);
e[v].pb(u);
Edge[i] = make_pair(u, v);
}
hi[1] = 1;
dfs(1, 1);
for(int j = 1; j < 17; j++) {
for(int i = 1; i <= n; i++) {
if(f[i][j - 1]) {
f[i][j] = f[f[i][j - 1]][j - 1];
}
}
}
for(int i = 1; i <= m; i++) {
int x, y;
cin >> x;
cin >> y;
a.pb(make_pair(y, x));
}
a.pb(make_pair(-1, -1));
for(int i = 1; i <= q; i++) {
cin >> h[i].u >> h[i].v >> h[i].gold >> h[i].silver;
L[i] = 0;
R[i] = m;
}
sort(all(a));
while(1) {
vector<ii>b;
for(int i = 1; i <= n; i++) bit[i] = 0, bit_canh[i] = 0;
for(int i = 1; i <= q; i++) {
if(L[i] <= R[i]) b.pb(make_pair((L[i] + R[i]) / 2, i));
}
if(b.size() == 0) break;
sort(all(b));
int pos = 1;
for(int i = 0; i < b.size(); i++) {
while(pos <= m && pos <= b[i].fi) {
int vt = a[pos].se;
int u = Edge[a[pos].se].fi;
int v = Edge[a[pos].se].se;
if(hi[u] > hi[v]) swap(u, v);
update(bit, tin[v], a[pos].fi);
update(bit_canh, tin[v], 1);
update(bit, tout[v] + 1, -a[pos].fi);
update(bit_canh, tout[v] + 1, -1);
pos++;
}
int vt = b[i].se;
int sum = get(bit, tin[h[vt].u]) + get(bit, tin[h[vt].v]) - 2 * get(bit, tin[lca(h[vt].u, h[vt].v)]);
int canh = get(bit_canh, tin[h[vt].u]) + get(bit_canh, tin[h[vt].v]) - 2 * get(bit_canh, tin[lca(h[vt].u, h[vt].v)]);
if(sum <= h[vt].silver) {
L[vt] = b[i].fi + 1;
need[vt] = canh;
}
else {
R[vt] = b[i].fi - 1;
}
}
}
for(int i = 1; i <= n; i++) bit_canh[i] = 0;
for(int i = 1; i <= m; i++) {
int vt = a[i].se;
int u = Edge[vt].fi;
int v = Edge[vt].se;
if(hi[u] > hi[v]) swap(u, v);
update(bit_canh, tin[v], 1);
update(bit_canh, tout[v] + 1, -1);
}
for(int i = 1; i <= q; i++) {
int cha = lca(h[i].u, h[i].v);
int can = get(bit_canh, tin[h[i].u]) + get(bit_canh, tin[h[i].v]) - 2 * get(bit_canh, tin[cha]) - need[i];
int res = h[i].gold - can;
if(res < 0) res = -1;
cout << res << "\n";
}
}
// ProTeam
//(¯`·.·´¯) (¯`·.·´¯)
//`·.¸(¯`·.·´¯)¸ .·
//×°× ` ·.¸.·´ ×°×
