//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx,avx2,fma,lzcnt,popcnt")
#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define ill pair<ll,ll>
#define el cout<<'\n'
#define int long long
const ll mod=1e9+7;
const int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
const int nmax=1e5;
const int inf =2e9;
void add(int &a, int b) {
a += b;
if (a >= mod) a -= mod;
if (a < 0) a += mod;
}
template<typename T> void chkmin(T& x, T y) {if(x > y) x = y;}
template<typename T> void chkmax(T& x, T y) {if(x < y) x = y;}
using namespace std;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r)
{
return uniform_int_distribution<int>(l, r) (rd);
}
int n,m;
int q;
ii cost[nmax + 5];
vector<int>adj[nmax + 5];
ii edge[nmax + 5];
int h[nmax + 5];
int par[nmax + 5][23];
int in[nmax + 5];
int out[nmax + 5];
int timer = 0;
void dfs(int u,int dad)
{
in[u] = ++timer;
for(auto v:adj[u])
{
if(v == dad) continue;
par[v][0] = u;
h[v] = h[u] + 1;
dfs(v,u);
}
out[u] = timer;
}
void prepare()
{
for(int i=1;i<=19;i++)
for(int j=1;j<=n;j++)
par[j][i] = par[par[j][i - 1]][i - 1];
}
int LCA(int u,int v)
{
if(h[v] > h[u])
swap(u,v);
for(int i=19;i>=0;i--)
{
if(h[par[u][i]] >= h[v])
u = par[u][i];
}
if(u == v) return u;
for(int i=19;i>=0;i--)
if(par[u][i] != par[v][i])
{
u = par[u][i];
v = par[v][i];
}
return par[u][0];
}
struct infor{
int s,t,x,y;
}citizen[nmax + 5];
struct parallel{
int L,R,ANS;
} ans[nmax + 5];
int fen_val[nmax + 5];
int fen_cnt[nmax + 5];
void update(int *bit, int idx, int val)
{
while(idx <= n)
{
bit[idx] += val;
idx += (idx&(-idx));
}
}
void updaterange(int *bit, int L,int R,int val)
{
update(bit, L,val);
update(bit, R + 1,-val);
}
int get(int *bit, int idx)
{
int res = 0;
while(idx)
{
res += bit[idx];
idx -= (idx&(-idx));
}
return res;
}
int get_path(int *bit, int u, int v, int lca) {
return get(bit, in[u]) + get(bit, in[v]) - 2 * get(bit, in[lca]);
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
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);
edge[i].fi = u;
edge[i].se = v;
}
dfs(1,-1);
prepare();
for(int i=1;i<=m;i++)
{
cin >> cost[i].se >> cost[i].fi;
}
sort(cost + 1,cost + 1 + m);
for(int i=1;i<=q;i++)
{
cin >> citizen[i].s >> citizen[i].t >> citizen[i].x >> citizen[i].y;
}
for(int i=1;i<=q;i++)
{
ans[i].L = 0;
ans[i].R = m;
ans[i].ANS = 0;
}
vector<int>bucket[nmax + 5];
while(true)
{
bool has_query = false;
for(int i=0; i<=m; i++) bucket[i].clear();
for(int i=1;i<=q;i++)
{
if(ans[i].L <= ans[i].R)
{
has_query = true;
int mid = (ans[i].L + ans[i].R) >> 1;
bucket[mid].pb(i);
}
}
if(!has_query) break;
for(int i=0;i<=n;i++) {
fen_val[i] = 0;
fen_cnt[i] = 0;
}
for(auto j : bucket[0]) {
ans[j].ANS = 0;
ans[j].L = 1;
}
for(int i=1;i<=m;i++)
{
int u = edge[cost[i].se].fi;
int v = edge[cost[i].se].se;
if(par[u][0] == v) swap(u,v);
updaterange(fen_val, in[v], out[v], cost[i].fi);
updaterange(fen_cnt, in[v], out[v], 1);
for(auto j:bucket[i])
{
int s = citizen[j].s;
int t = citizen[j].t;
int lca = LCA(s, t);
int sliver = citizen[j].y;
int need = get_path(fen_val, s, t, lca);
int checkpoint = get_path(fen_cnt, s, t, lca);
if(sliver >= need)
{
ans[j].ANS = checkpoint;
ans[j].L = i + 1;
}
else
ans[j].R = i - 1;
// cout << ans[j].L << " " << ans[j].R << " " << ans[j].ANS;el;
}
}
}
for(int i=0;i<=n;i++) fen_cnt[i] = 0;
for(int i=1;i<=m;i++)
{
int u = edge[cost[i].se].fi;
int v = edge[cost[i].se].se;
if(par[u][0] == v) swap(u,v);
updaterange(fen_cnt, in[v], out[v], 1);
}
for(int i=1;i<=q;i++)
{
int s = citizen[i].s;
int t = citizen[i].t;
int total = get_path(fen_cnt, s, t, LCA(s, t));
int gold_needed = total - ans[i].ANS;
// cout << total << " " << gold_needed << " " << citizen[i].x;el;
if(citizen[i].x - gold_needed >= 0)
cout << citizen[i].x - gold_needed;
else cout << -1;
el;
}
}
//Can i get a kiss? And can u make it last forever?
