#include <bits/stdc++.h>
using namespace std;
const int maxn = 300005;
const int sqr = 317;
typedef long long ll;
#define int ll
ll decomp1[maxn];
ll arr1[maxn];
ll decomp2[maxn];
ll arr2[maxn];
int tin[maxn],tout[maxn];
int par[maxn];
int times = 0;
vector<int> eul;
vector<int> edg;
int c[maxn];
vector<vector<pair<int,int>>> g;
int L = 0,R = 0;
int ul = 0,ur = 0;
void modify(int i,int x)
{
//cout << "mod " << i << ' ' << x << endl;
arr1[i] += x;
decomp1[i/sqr] += x;
arr2[i] += (x > 0 ? 1 : (x < 0 ? -1 : 0));
decomp2[i/sqr] += (x > 0 ? 1 : (x < 0 ? -1 : 0));
}
void dfs(int v,int p,int pe)
{
par[v] = p;
tin[v] = times++;
eul.push_back(v);
if(p != -1)
edg.push_back(pe);
for(auto [u,i]:g[v])
{
if(u != p)
{
dfs(u,v,i);
eul.push_back(v);
edg.push_back(i);
}
}
tout[v] = times;
}
bool isP(int u,int v)
{
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
bool ch(int v,bool f)
{
if(!f)
{
swap(ul,ur);
}
bool ans = false;
if(!isP(ul,ur))
{
if(v == par[ul])
{
ans = false;
}
else
{
ans = true;
}
}
else
{
if(ul == ur)
ans = true;
else if(v == par[ul] || !isP(v,ur))
{
ans = true;
}
else
ans = false;
}
ul = v;
if(!f)
swap(ul,ur);
return ans;
}
void go_ll()
{
L--;
if(ch(eul[L],1))
modify(edg[L],c[edg[L]]);
else
modify(edg[L],-c[edg[L]]);
}
void go_lr()
{
L++;
if(ch(eul[L],1))
modify(edg[L-1],c[edg[L-1]]);
else
modify(edg[L-1],-c[edg[L-1]]);
}
void go_rl()
{
R--;
if(ch(eul[R],0))
modify(edg[R],c[edg[R]]);
else
modify(edg[R],-c[edg[R]]);
}
void go_rr()
{
R++;
if(ch(eul[R],0))
modify(edg[R-1],c[edg[R-1]]);
else
modify(edg[R-1],-c[edg[R-1]]);
}
struct que
{
que(ll _s,ll _t,ll _x,ll _y,ll _i){s = _s;t = _t;x = _x;y = _y;i = _i;};
ll s,t,x,y,i;
bool operator < (const que & oth){return (s/sqr != oth.s/sqr ? s < oth.s : t < oth.t);};
};
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n,m,q;
cin >> n >> m >> q;
vector<pair<int,int>> e;
vector<vector<int>> ch(n-1);
for(int j = 0;j < n-1;++j)
{
int a,b;
cin >> a >> b;
a--;
b--;
e.push_back({a,b});
}
vector<pair<int,int>> ed;
for(int j = 0;j < m;++j)
{
int p,c;
cin >> p >> c;
p--;
ed.push_back({c,p});
}
sort(ed.begin(),ed.end());
for(int j = 0;j < ed.size();++j)
{
c[j+1] = ed[j].first;
ch[ed[j].second].push_back(j+1);
}
int yk = n;
vector<pair<pair<int,int>,int>> ee;
for(int j = 0;j < n-1;++j)
{
if(ch[j].size() == 0)
{
ee.push_back({{e[j].first,e[j].second},0});
}
else
{
int st = e[j].first,en = e[j].second;
for(int y = 0;y < ch[j].size();++y)
{
int fv = (y == 0 ? st : yk++);
int sv = (y+1 == ch[j].size() ? en : yk);
ee.push_back({{fv,sv},ch[j][y]});
}
}
}
g.resize(yk);
for(int u= 0;u < ee.size();++u)
{
int v1 = ee[u].first.first,v2 = ee[u].first.second,i = ee[u].second;
//cout << v1 << ' ' << v2 << ' ' << i << ' ' << c[i] << "\n";
g[v1].push_back({v2,i});
g[v2].push_back({v1,i});
}
dfs(0,-1,-1);
vector<int> pos(yk);
for(int y = 0;y < eul.size();++y)
{
pos[eul[y]] = y;
}
vector<que> queries;
for(int i =0;i < q;++i)
{
ll s,t,x,y;
cin >> s >> t >> x >> y;
s--;
t--;
s = pos[s];
t = pos[t];
if(s > t)
swap(s,t);
//cout << s << ' ' << t << endl;
queries.push_back(que(s,t,x,y,i));
}
sort(queries.begin(),queries.end());
int res[q];
for(int j = 0;j < queries.size();++j)
{
int s = queries[j].s,t = queries[j].t,x = queries[j].x,y = queries[j].y,ii = queries[j].i;
while(L > s)
go_ll();
while(R < t)
go_rr();
while(L < s)
go_lr();
while(R > t)
go_rl();
// cout << "! " << s << ' ' << t << ' ' << x << ' ' << y << ' ' << decomp1[0] << ' ' << arr2[1] << endl;
ll sum = 0;
ll ans = 0;
int pos = m+1;
for(int i = 0;i < sqr;++i)
{
if(sum+decomp1[i] <= y)
{
sum += decomp1[i];
}
else
{
for(int l = i*sqr;l < (i+1)*sqr;++l)
{
//cout << arr1[l] << endl;
if(sum + arr1[l] <= y)
{
sum += arr1[l];
}
else
{
pos = l;
break;
}
}
break;
}
}
//cout << pos << endl;
while(pos < m+1 && pos%sqr)
{
ans += arr2[pos++];
}
//cout << ans << endl;
while(pos < m+1)
{
ans += decomp2[pos/sqr];
pos += sqr;
}
res[ii] = (x >= ans ? x-ans : -1);
}
for(int i = 0;i < q;++i)
cout << res[i] << "\n";
}
