#include<bits/stdc++.h>
using namespace std;
// define
#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ii pair <int , int>
#define iii pair <int , ii>
#define se second
#define fi first
#define all(v) (v).begin() , (v).end()
#define Unique(v) sort(all(v)) , v.resize(unique(all(v)) - v.begin())
#define bit(x,i) (((x) >> (i)) & 1LL)
#define flip(x,i) ((x) ^ (1LL << (i)))
#define ms(d,x) memset(d , x , sizeof(d))
#define exist __exist
#define ends __ends
#define visit visited
#define left __left
#define right __right
#define prev __prev
#define next __next
#define sitingfake 1
#define orz 1
//constant
const long long mod = 1e9 + 7;
const long long linf = 4557430888798830399LL;
const long long nlinf = -4485090715960753727LL;
const int LOG = 20;
const int inf = 1061109567;
const int ninf = -1044266559;
const int dx[] = {0 , -1 , 0 , 1};
const int dy[] = {-1 , 0 , 1 , 0};
template<typename T> bool maximize(T &a, const T &b)
{
if(a < b) {a = b; return 1;}
return 0;
}
template<typename T> bool minimize(T &a, const T &b)
{
if(a > b) {a = b; return 1;}
return 0;
}
void Plus(ll & a ,ll b)
{
b %= mod;
a += b;
if(a < 0) a += mod;
a %= mod;
return;
}
void Mul(ll & a, ll b)
{
(a *= (b % mod)) %= mod;
return;
}
//code
const int maxn = 1e5 + 7;
int n , m , q;
ii CheckPoint[maxn] , edges[maxn];
bool cmp(ii &a , ii & b)
{
return a.se < b.se;
}
struct Query
{
int u , v;
ll Gold , Silver;
int id;
}Q[maxn];
int left[maxn] , right[maxn] , ans[maxn];
vector <int> Query[maxn];
// HLD
int in[maxn] , out[maxn] , timer;
int pos[maxn];
vector <int> adj[maxn];
int head[maxn] , heavy[maxn] , par[maxn] , depth[maxn];
int num[maxn];
int dfscount(int u , int p)
{
int cur = 1;
int Max = 0;
for(int v : adj[u])
{
if(v != p)
{
par[v] = u;
depth[v] = depth[u] + 1;
int sz = dfscount(v , u);
if(maximize(Max , sz))
{
heavy[u] = v;
}
cur += sz;
}
}
return cur;
}
void HLD(int u , int p , int h)
{
head[u] = h;
in[u] = ++timer;
if(heavy[u])
{
HLD(heavy[u] , u , h);
}
for(int v : adj[u])
{
if(v != p && v != heavy[u])
{
HLD(v , u , v);
}
}
}
void dfs(int u , int p)
{
for(int v : adj[u])
{
if(v != p)
{
num[v] += num[u];
dfs(v , u);
}
}
}
void init()
{
for(int i = 1; i < n; i++)
{
int u = edges[i].fi;
int v = edges[i].se;
if(in[u] <= in[v] && out[v] <= out[u])
{
swap(u , v);
swap(edges[i].fi , edges[i].se);
}
pos[i] = in[u];
}
for(int i = 1; i <= m; i++)
{
num[edges[CheckPoint[i].fi].fi]++;
}
dfs(1 , -1);
for(int i = 1; i <= q; i++)
{
left[i] = 1 , right[i] = m;
}
}
// query
pair <int , ll> bit[maxn];
void up(int x , int num , ll coins)
{
for(;x <= n; x += (x & -x))
{
bit[x].fi += num;
bit[x].se += coins;
}
}
pair <int , ll> get(int x)
{
pair <int , ll> ans = {0 , 0};
for(;x > 0; x -= (x & -x))
{
ans.fi += bit[x].fi;
ans.se += bit[x].se;
}
return ans;
}
pair <int , ll> RangeQuery(int l , int r)
{
if(l > r) return {0 , 0};
pair <int ,ll> left = get(l - 1) , right = get(r);
return {right.fi - left.fi , right.se - left.se};
}
void reset()
{
for(int i = 1; i <= n; i++)
{
bit[i] = {0 , 0};
}
}
pair <int , ll> PathQuery(int u , int v)
{
pair <int , ll> ans = {0 , 0};
for(;head[v] != head[u]; v = par[head[v]])
{
if(depth[head[u]] > depth[head[v]]) swap(u , v);
pair <int , ll> tmp = RangeQuery(in[head[v]] , in[v]);
ans.fi += tmp.fi;
ans.se += tmp.se;
}
if(depth[u] > depth[v]) swap(u , v);
pair <int , ll> tmp = RangeQuery(in[u] + 1 , in[v]);
ans.fi += tmp.fi;
ans.se += tmp.se;
return ans;
}
int lca(int u , int v)
{
for(;head[u] != head[v]; v = par[head[v]])
{
if(depth[head[u]] > depth[head[v]]) swap(u , v);
}
if(depth[u] > depth[v]) swap(u , v);
return u;
}
void Process()
{
reset();
for(int d = 1; d <= m; d++)
{
up(pos[CheckPoint[d].fi] , 1 , CheckPoint[d].se);
for(int i : Query[d])
{
pair <int , ll> tmp = PathQuery(Q[i].u , Q[i].v);
if(tmp.se <= Q[i].Silver)
{
ans[i] = tmp.fi;
left[i] = d + 1;
}
else
{
right[i] = d - 1;
}
}
Query[d].clear();
}
}
void solve(void)
{
cin >> n >> m >> q;
for(int i = 1; i < n; i++)
{
int u , v; cin >> u >> v;
edges[i] = {u , v};
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i = 1; i <= m; i++)
{
cin >> CheckPoint[i].fi >> CheckPoint[i].se;
}
for(int i = 1; i <= q; i++)
{
cin >> Q[i].u >> Q[i].v >> Q[i].Gold >> Q[i].Silver;
}
sort(CheckPoint + 1 , CheckPoint + m + 1 , cmp);
dfscount(1 , -1);
HLD(1 , -1 , 1);
init();
while(1) {
bool flag = 1;
for(int i = 1; i <= q; i++)
{
if(left[i] <= right[i])
{
flag = 0;
Query[(left[i] + right[i]) >> 1].push_back(i);
}
}
if(flag) break;
Process();
}
for(int i = 1; i <= q; i++)
{
int curPoint = num[Q[i].u] + num[Q[i].v] - 2 * num[lca(Q[i].u , Q[i].v)];
curPoint -= ans[i];
if(Q[i].Gold - curPoint < 0)
{
cout << -1 << "\n";
}
else cout << Q[i].Gold - curPoint << "\n";
}
}
/**
5 4 1
1 2
1 3
2 4
2 5
2 9
2 4
3 5
4 7
3 4 2 11
**/
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task ""
if(fopen(task".inp","r"))
{
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) solve();
// execute;
}
