#include <bits/stdc++.h>
using namespace std;
long long par[100005][20], edge[100005], depth[100005], in[100005], out[100005], l1[100005], r1[100005], l2[100005], r2[100005], x[100005], y[100005], ans[100005], bit[200005], bit2[200005], n, m, q, sz;
vector<pair<long long, long long> > adj[100005], upd;
void dfs(long long u, long long p)
{
par[u][0]=p;
for (long long i=1; i<20; i++)
par[u][i]=par[par[u][i-1]][i-1];
for (long long i=0; i<adj[u].size(); i++)
{
long long v=adj[u][i].first, w=adj[u][i].second;
if (v==p)
continue;
depth[v]=depth[u]+1;
edge[v]=w;
in[w]=(++sz);
dfs(v, u);
out[w]=(++sz);
}
}
void update(long long s, long long t)
{
for (long long i=s; i<=sz; i+=i&(-i))
{
bit[i]+=t;
if (t>0)
bit2[i]++;
else
bit2[i]--;
}
}
long long query(long long s)
{
long long res=0;
for (long long i=s; i>=1; i-=i&(-i))
res+=bit[i];
return res;
}
long long query2(long long s)
{
long long res=0;
for (long long i=s; i>=1; i-=i&(-i))
res+=bit2[i];
return res;
}
void recur(long long L, long long R, vector<long long> vec)
{
if (L==R)
{
for (long long ind:vec)
{
long long res=query2(r1[ind])-query2(l1[ind]-1);
if (l2[ind])
res+=query2(r2[ind])-query2(l2[ind]-1);
ans[ind]=res;
}
return;
}
long long mid=(L+R+1)/2;
for (long long i=L; i<mid; i++)
{
update(in[upd[i].second], upd[i].first);
update(out[upd[i].second], -upd[i].first);
}
vector<long long> ok, notok;
for (long long ind:vec)
{
long long res=query(r1[ind])-query(l1[ind]-1);
if (l2[ind])
res+=query(r2[ind])-query(l2[ind]-1);
if (res<=y[ind])
ok.push_back(ind);
else
notok.push_back(ind);
}
if (ok.size())
recur(mid, R, ok);
for (long long i=L; i<mid; i++)
{
update(in[upd[i].second], -upd[i].first);
update(out[upd[i].second], upd[i].first);
}
if (notok.size())
recur(L, mid-1, notok);
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m >> q;
for (long long i=1; i<n; i++)
{
long long u, v;
cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfs(1, 1);
for (long long i=0; i<m; i++)
{
long long s, t;
cin >> s >> t;
upd.push_back({t, s});
}
sort(upd.begin(), upd.end());
for (long long i=1; i<=q; i++)
{
long long a, b, curA, curB;
cin >> a >> b >> x[i] >> y[i];
if (depth[a]<depth[b])
swap(a, b);
curA=a, curB=b;
if (depth[a]>depth[b])
{
for (long long j=19; j>=0; j--)
if ((depth[a]-depth[b]-1)&(1<<j))
curA=par[curA][j];
if (par[curA][0]==curB)
{
l1[i]=in[edge[curA]];
r1[i]=in[edge[a]];
l2[i]=-1;
continue;
}
curA=par[curA][0];
}
for (long long j=19; j>=0; j--)
{
if (par[curA][j]!=par[curB][j])
{
curA=par[curA][j];
curB=par[curB][j];
}
}
l1[i]=in[edge[curA]];
r1[i]=in[edge[a]];
l2[i]=in[edge[curB]];
r2[i]=in[edge[b]];
}
vector<long long> tmp;
for (long long i=1; i<=q; i++)
tmp.push_back(i);
recur(0, m, tmp);
for (long long i=0; i<m; i++)
{
update(in[upd[i].second], upd[i].first);
update(out[upd[i].second], -upd[i].first);
}
for (long long i=1; i<=q; i++)
{
long long res=query2(r1[i])-query2(l1[i]-1);
if (l2[i])
res+=query2(r2[i])-query2(l2[i]-1);
cout << max(-1LL, x[i]-(res-ans[i])) << '\n';
}
}
