#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(a) a.begin(),a.end()
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef unsigned long long ull;
template<const int MOD> struct mint{
int val;
constexpr mint(int x = 0) : val((x%=MOD) + (x<0?MOD:0)) {;}
mint& operator+=(const mint &b){val+=b.val; val-=MOD*(val>=MOD); return *this;}
mint& operator-=(const mint &b){val-=b.val; val+=MOD*(val<0); return *this;}
mint& operator*=(const mint &b){val=1ll*val*b.val%MOD; return *this;}
mint& operator/=(const mint &b){return *this *= b.inv();}
mint inv() const {
int x = 1, y = 0, t;
for(int a=val, b=MOD; b; swap(a,b), swap(x,y))
t = a/b, a-=t*b, x-=t*y;
return mint(x);
}
mint pow(int b) const{
if(b<0) b += MOD-1;
mint a = *this, res(1);
for(; b>0; a*=a, b>>=1) if(b&1) res *= a;
return res;
}
friend mint operator+(const mint &a, const mint &b) { return mint(a) += b; }
friend mint operator-(const mint &a, const mint &b) { return mint(a) -= b; }
friend mint operator*(const mint &a, const mint &b) { return mint(a) *= b; }
friend mint operator/(const mint &a, const mint &b) { return mint(a) /= b; }
friend bool operator==(const mint &a, const mint &b) { return a.val == b.val; }
friend bool operator!=(const mint &a, const mint &b) { return a.val != b.val; }
friend bool operator<(const mint &a, const mint &b) { return a.val < b.val; }
friend ostream& operator<<(ostream &os, const mint &a) { return os << a.val; }
};
const int mxn = 1e5+1, mxa = 18e5;
vector<pii> g[mxn];
vector<int> check[mxn];
vector<int> vec[mxn];
int dep[mxn], par[mxn];
int qu[mxn][4];
ll qu2[mxn];
bool vis[mxn];
int sz[mxa], pl[mxa], pr[mxa], node = 0;
int pos[mxn], root[mxn], len;
ll st[mxa];
int update(int cur, int l, int r, int k){
int id = ++node;
if(l==r){st[id]=st[cur]+pos[l],sz[id]=sz[cur]+1; return id;}
int m = (l+r)>>1;
if(k <= m) pl[id] = update(pl[cur],l,m,k), pr[id] = pr[cur];
else pr[id] = update(pr[cur],m+1,r,k), pl[id] = pl[cur];
st[id] = st[pl[id]] + st[pr[id]];
sz[id] = sz[pl[id]] + sz[pr[id]];
return id;
}
int find(int u){
if(par[u]<0) return u;
return par[u]=find(par[u]);
}
void dfs(int u, int p){
vis[u] = 1; par[u] = -1;
for(auto i : vec[u]){
int v = qu[i][0]^qu[i][1]^u;
if(vis[v]) qu[i][3] = find(v);
}
for(auto [v,i] : g[u]) if(v!=p){
root[v] = root[u];
dep[v] = dep[u];
for(auto c : check[i]){
c = lower_bound(pos,pos+len,c)-pos;
root[v] = update(root[v],0,len-1,c);
dep[v]++;
}
dfs(v,u); par[v] = u;
}
}
int get(int u, int v, int lca, int l, int r, ll rem){
if(l==r){
ll cur = st[u]+st[v]-2*st[lca];
if(cur <= rem) return sz[u]+sz[v]-2*sz[lca];
else return rem/pos[l];
}
int m = (l+r)>>1;
ll cur = st[pl[u]] + st[pl[v]] - 2*st[pl[lca]];
if(cur >= rem) return get(pl[u],pl[v],pl[lca],l,m,rem);
else return get(pr[u],pr[v],pr[lca],m+1,r,rem - cur) + sz[pl[u]] + sz[pl[v]] - 2*sz[pl[lca]];
}
void solve(){
int n,k,q; cin >> n >> k >> q;
for(int i = 1; i < n; i++){
int u,v; cin >> u >> v;
g[u].emplace_back(pii{v,i});
g[v].emplace_back(pii{u,i});
}
for(int i = 1; i <= k; i++){
int p,c; cin >> p >> c;
check[p].emplace_back(c);
pos[i] = c;
}
sort(pos,pos+k+1);
len = unique(pos,pos+k+1)-pos;
for(int i = 1; i <= q; i++){
cin >> qu[i][0] >> qu[i][1] >> qu[i][2] >> qu2[i];
vec[qu[i][0]].emplace_back(i);
vec[qu[i][1]].emplace_back(i);
}
dfs(1,1);
for(int i = 1; i <= q; i++){
int u = qu[i][0], v = qu[i][1], lca = qu[i][3];
cout << max(-1, qu[i][2] - (dep[u]+dep[v]-2*dep[lca] - get(root[u],root[v],root[lca],0,len-1,qu2[i]))) << '\n';
}
}
signed main(){
cin.tie(0)->sync_with_stdio(0);
int t = 1;
// cin >> t;
while(t--){solve();}
}
