#include <bits/stdc++.h>
#define int long long
#define debug(x) if(0) cout << #x << " is " << x << endl;
using namespace std;
int N, M, Q;
struct node{
int32_t S, E, M;
int V;
node *l, *r;
//range add, point query
node(int _S, int _E){
S = _S;
E = _E;
V = 0;
l = r = NULL;
M = (S + E) >> 1;
}
node* cpy(){
node *ret = new node(S, E);
ret->S = S;
ret->E = E;
ret->l = l;
ret->r = r;
ret->M = M;
ret->V = V;
return ret;
}
int query(int start, int end){
if(start == S && end == E){
return V;
}
if(end <= M){
if(l == NULL) return 0;
return l->query(start, end);
}
if(start > M){
if(r == NULL) return 0;
return r->query(start, end);
}
int lAns, rAns;
if(l == NULL) lAns = 0;
else lAns = l->query(start, M);
if(r == NULL) rAns = 0;
else rAns = r->query(M + 1, end);
return lAns + rAns;
}
void upd(int idx, int val){
if(S == E){
V += val;
return;
}
if(idx <= M){
if(l) l = l->cpy();
else l = new node(S, M);
l->upd(idx, val);
}
else{
if(r) r = r->cpy();
else r = new node(M + 1, E);
r->upd(idx, val);
}
V += val;
}
}*seggssum, *seggscnt;
const int maxN = 1e5 + 5;
vector<int> adj[maxN];
int order[maxN];
int cur = 0;
int mem[maxN][20];
int depth[maxN];
int streesz[maxN];
void dfs(int x, int par){
order[x] = cur++;
mem[x][0] = par;
streesz[x] = 1;
for(auto j:adj[x]){
if(j == par) continue;
depth[j] = depth[x] + 1;
dfs(j, x);
streesz[x] += streesz[j];
}
}
int anc(int x, int k){
int cur = x;
for(int i=19;i>=0;i--){
if(((1 << i) & k) != 0){
cur = mem[cur][i];
}
}
return cur;
}
int lcaa(int x, int y){
if(depth[x] < depth[y]) swap(x, y);
int k = depth[x] - depth[y];
x = anc(x, k);
assert(min(x, y) >= 1);
assert(k >= 0);
if(x == y) return x;
for(int i=19;i>=0;i--){
if(mem[x][i] != mem[y][i]){
x = mem[x][i];
y = mem[y][i];
}
}
return mem[x][0];
}
main(){
cin >> N >> M >> Q;
seggssum = new node(0, N + 5);
seggscnt = new node(0, N + 5);
int A[N], B[N];
for(int i=1;i<=N-1;i++) cin >> A[i] >> B[i];
for(int i=1;i<=N-1;i++){
adj[A[i]].push_back(B[i]);
adj[B[i]].push_back(A[i]);
}
depth[1] = 0;
dfs(1, -1);
//2k
for(int j=1;j<20;j++){
for(int i=1;i<=N;i++){
int hpar = mem[i][j-1];
if(hpar == -1) mem[i][j] = -1;
else mem[i][j] = mem[hpar][j-1];
}
}
int C[M], P[M];
for(int i=0;i<M;i++){
cin >> P[i] >> C[i];
}
int S[Q], T[Q], X[Q], Y[Q], lca[Q];
for(int i=0;i<Q;i++){
cin >> S[i] >> T[i] >> X[i] >> Y[i];
lca[i] = lcaa(S[i], T[i]);
}
vector<pair<int, int>> V;
for(int i=0;i<M;i++){
V.push_back({C[i], P[i]});
}
sort(V.begin(), V.end());
node* sum[M + 5];
node* count[M + 5];
sum[0] = seggssum;
count[0] = seggscnt;
for(int i=1;i<=M;i++){
int x = V[i-1].second;
int bruh = A[x];
if(depth[B[x]] >= depth[bruh]) bruh = B[x];
sum[i] = sum[i-1]->cpy();
sum[i]->upd(order[bruh], V[i-1].first);
sum[i]->upd(order[bruh] + streesz[bruh], -V[i-1].first);
count[i] = count[i-1]->cpy();
count[i]->upd(order[bruh], 1);
count[i]->upd(order[bruh] + streesz[bruh], -1);
}
debug("hi");
for(int i=0;i<Q;i++){
int lb = 0;
int ub = M;
while(ub > lb){
int m = (ub + lb + 1) >> 1;
int s = sum[m]->query(0, order[S[i]]);
int t = sum[m]->query(0, order[T[i]]);
int l = sum[m]->query(0, order[lca[i]]);
if((s + t - (2 * l)) <= Y[i]) lb = m;
else ub = m - 1;
}
int s = count[lb]->query(0, order[S[i]]);
int t = count[lb]->query(0, order[T[i]]);
int l = count[lb]->query(0, order[lca[i]]);
int k = s + t - (2 * l);
s = count[M]->query(0, order[S[i]]);
t = count[M]->query(0, order[T[i]]);
l = count[M]->query(0, order[lca[i]]);
int tot = s + t - (2 * l);
int nec = tot - k;
int res = X[i] - nec;
if(res < 0){
cout << "-1\n";
}
else cout << res << '\n';
}
for(int i=1;i<=N;i++) debug(order[i]);
}
