#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define F first
#define S second
#define all(p) p.begin(),p.end()
using namespace std;
const int mod = 20071008;
const int INF=1e18;
const int N = 1e5 + 5, M=1e6+5;
int n, m, q, c[N], l[N], r[N], s[N], t[N], x[N], y[N], a[N], cnt[N], par[N], h[N], Index[N], head[N], pos=1, id=1, res[N];
vector<int> e[N], qr[N];
pii ed[N];
void file()
{
#define task "main"
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
}
void add(int &A, int B)
{
A+=B;
if(A>=mod) A-=mod;
}
void maximum(int &A, int B)
{
if(A<B) A=B;
}
struct edge
{
int u=0, v=0, w=0;
bool operator< (const edge &a)
{
return w<a.w;
}
} ev[N];
struct FenwickTree
{
struct node
{
int val=0, cnt=0;
node() {}
node(int val, int cnt): val(val), cnt(cnt) {}
};
int n;
vector<node> bit;
void init(int _n)
{
n=_n;
bit.resize(n+5);
}
void reset()
{
for(int i=1; i<=n; ++i) bit[i]={0,0};
}
node mer(node left, node right)
{
return node(left.val+right.val,left.cnt+right.cnt);
}
void update(int i, int val)
{
for(; i<=n; i+=i&-i) bit[i]=mer(bit[i],node(val,1));
}
node get(int i)
{
node res(0,0);
for(; i>0; i-=i&-i) res=mer(res,bit[i]);
return res;
}
node get(int l, int r)
{
node tmp1=get(r), tmp2=get(l-1);
return node(tmp1.val-tmp2.val,tmp1.cnt-tmp2.cnt);
}
} BIT;
void DFS(int u)
{
cnt[u]=1;
for(int v: e[u])
{
if(v==par[u]) continue;
par[v]=u;
DFS(v);
cnt[u]+=cnt[v];
}
}
void dfs(int u)
{
for(int v: e[u])
{
if(v==par[u]) continue;
h[v]+=h[u];
dfs(v);
}
}
void HLD(int u)
{
if(head[id]==0) head[id]=u;
Index[u]=id;
a[u]=pos++;
int nxt=0;
for(int v: e[u]) if(v!=par[u] and cnt[v]>cnt[nxt]) nxt=v;
if(nxt) HLD(nxt);
for(int v: e[u])
{
if(v==par[u] or v==nxt) continue;
++id;
HLD(v);
}
}
int lca(int u, int v)
{
while(Index[u]!=Index[v])
{
if(Index[u]>Index[v]) u=par[head[Index[u]]];
else v=par[head[Index[v]]];
}
if(a[u]<a[v]) return u;
return v;
}
int distance(int u, int v)
{
int p=lca(u,v);
return h[u]+h[v]-2*h[p];
}
FenwickTree::node query(int u, int v)
{
int p=lca(u,v);
FenwickTree::node res(0,0);
while(Index[u]!=Index[p])
{
res=BIT.mer(res,BIT.get(a[head[Index[u]]],a[u]));
u=par[head[Index[u]]];
}
while(Index[v]!=Index[p])
{
res=BIT.mer(res,BIT.get(a[head[Index[v]]],a[v]));
v=par[head[Index[v]]];
}
if(a[u]<a[v]) res=BIT.mer(res,BIT.get(a[u],a[v]));
else res=BIT.mer(res,BIT.get(a[v],a[u]));
return res;
}
void Solve()
{
cin>>n>>m>>q;
for(int i=1; i<n; ++i)
{
cin>>ed[i].F>>ed[i].S;
e[ed[i].F].push_back(ed[i].S);
e[ed[i].S].push_back(ed[i].F);
}
BIT.init(n);
DFS(1);
HLD(1);
for(int i=1; i<n; ++i) if(a[ed[i].F]<a[ed[i].S]) swap(ed[i].F,ed[i].S);
for(int i=1; i<=m; ++i)
{
int p, c; cin>>p>>c;
ev[i]={ed[p].F,ed[p].S,c};
++h[ed[p].F];
}
dfs(1);
sort(ev+1,ev+m+1);
for(int i=1; i<=q; ++i)
{
cin>>s[i]>>t[i]>>x[i]>>y[i];
l[i]=1;
r[i]=m;
}
while(1)
{
bool ok=false;
for(int i=1; i<=q; ++i)
{
if(l[i]<=r[i])
{
ok=true;
qr[(l[i]+r[i])>>1].push_back(i);
}
}
if(!ok) break;
for(int i=1; i<=m; ++i)
{
int u=ev[i].u, w=ev[i].w;
BIT.update(a[u],w);
for(int it: qr[i])
{
FenwickTree::node tmp=query(s[it],t[it]);
if(tmp.val<=y[it]) l[it]=i+1;
else r[it]=i-1;
}
}
for(int i=1; i<n; ++i) qr[i].clear();
BIT.reset();
}
for(int i=1; i<=q; ++i) qr[r[i]].push_back(i);
for(int i=0; i<=m; ++i)
{
if(i>0)
{
int u=ev[i].u, w=ev[i].w;
BIT.update(a[u],w);
}
for(int it: qr[i])
{
FenwickTree::node tmp=query(s[it],t[it]);
int d=max(0ll,distance(s[it],t[it])-tmp.cnt);
if(d<=x[it]) res[it]=x[it]-d;
else res[it]=-1;
}
}
for(int i=1; i<=q; ++i) cout<<res[i]<<"\n";
}
signed main()
{
file();
Solve();
return 0;
}
