#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
struct node {
long long val;
int cnt;
node *left, *right;
node(long long val, int cnt, node* left, node *right) : val(val), cnt(cnt), left(left), right(right) {};
};
node *perstree[100001];
int in[100001];
int out[100001];
int height[100001];
int bl[100001][20];
pair<int,int> edges[100001];
vector<pair<int,int>> graph[100001];
vector<pair<int,int>> vctr;
int n;
int total[100001];
int borders[100001];
long long getval(node *n) {
if (n)return n->val;
else return 0;
}
int getcnt(node *n) {
if (n)return n->cnt;
else return 0;
}
node* build(int a, int b) {
if (a > b)return NULL;
if (a == b) {
return new node(0,0,NULL,NULL);
}
return new node(0,0,build(a,(a+b)/2),build((a+b)/2+1,b));
}
node* update(node *n, int a, int b, int x, long long v, int c) {
// printf("%d %d %d %lld\n",a,b,x,v);
if (a > b)return NULL;
if (a == b) {
// printf("%d : %lld + %lld , %d + %d\n",a,n->val,v,n->cnt,c);
return new node(n->val+v,n->cnt+c,NULL,NULL);
}
node* nleft;
node* nright;
if (x <= (a+b)/2) {
nleft = update(n->left,a,(a+b)/2,x,v,c);
nright = n->right;
} else if (x >= (a+b)/2+1) {
nright = update(n->right,(a+b)/2+1,b,x,v,c);
nleft = n->left;
}
// printf("%d-%d : %lld -> %lld , %d -> %d\n",a,b,n->val,getval(nleft)+getval(nright),n->cnt,getcnt(nleft)+getcnt(nright));
return new node(getval(nleft)+getval(nright),getcnt(nleft)+getcnt(nright),nleft,nright);
}
pair<long long,int> query(node *n, int a, int b, int x, int y) {
if (a > b || b < x || y < a)return {0,0};
if (x <= a && b <= y) {
// printf("%d=%d : %lld , %d\n",a,b,n->val,n->cnt);
return {n->val,n->cnt};
}
pair<long long,int> qleft, qright;
if (y <= (a+b)/2) {
qleft = query(n->left,a,(a+b)/2,x,y);
qright = {0,0};
} else if (x >= (a+b)/2+1) {
qright = query(n->right,(a+b)/2+1,b,x,y);
qleft = {0,0};
} else {
qleft = query(n->left,a,(a+b)/2,x,y);
qright = query(n->right,(a+b)/2+1,b,x,y);
}
// printf("%d==%d %d %d: %lld , %d\n",a,b,x,y,qleft.f+qright.f,qleft.s+qright.s);
return {qleft.f+qright.f,qleft.s+qright.s};
}
void findsize(int node, int pa, int h) {
height[node] = h;
if (pa != -1) {
bl[node][0] = pa;
}
if (pa != -1)bl[node][0] = pa;
for (auto it : graph[node]) {
if (it.f == pa)continue;
findsize(it.f,node,h+1);
}
return;
}
void findborders(int node, int pa, int b) {
total[node] = b;
for (auto it : graph[node]) {
if (it.f == pa)continue;
findborders(it.f,node,b+borders[it.f]);
}
return;
}
int timer = 1;
void eulertour(int node, int pa) {
in[node] = timer;
++timer;
for (auto it : graph[node]) {
if (it.f == pa) {
edges[it.s] = {it.f,node};
continue;
}
eulertour(it.f,node);
}
out[node] = timer;
return;
}
int findlca(int a, int b) {
if (height[a] != height[b]) {
if (height[b] < height[a]) {
swap(a,b);
}
for (int dist = height[b]-height[a]; dist > 0; dist -= dist&-dist) {
b = bl[b][(int)log2(dist&-dist)];
}
}
int cap1 = floor(log2(n));
for (;a != b;) {
int l = -1;
int r = cap1;
for (;;) {
if (l >= r)break;
int m = (l+r+1)/2;
if (bl[a][m] == bl[b][m]) {
r = m-1;
} else {
l = m;
}
}
if (l == -1) {
l = 0;
}
a = bl[a][l];
b = bl[b][l];
cap1 = l-1;
}
return a;
}
pair<long long,int> path(int amt, int u, int v, int lca) {
pair<long long,int> qu, qv, qlca;
qu = query(perstree[amt],1,n+1,1,in[u]);
qv = query(perstree[amt],1,n+1,1,in[v]);
qlca = query(perstree[amt],1,n+1,1,in[lca]);
// printf("%lld %d %lld %d %lld %d\n",qu.f,qu.s,qv.f,qv.s,qlca.f,qlca.s);
return {qu.f+qv.f-2*qlca.f,qu.s+qv.s-2*qlca.s};
}
int tcoins(int u, int v, int lca) {
return total[u]+total[v]-2*total[lca];
}
int main() {
int m, q;
scanf("%d%d%d",&n,&m,&q);
for (int i = 1; i <= n-1; ++i) {
int a, b;
scanf("%d%d",&a,&b);
graph[a].push_back({b,i});
graph[b].push_back({a,i});
}
for (int i = 0; i < m; ++i) {
int p, c;
scanf("%d%d",&p,&c);
vctr.push_back({c,p});
}
vctr.push_back({-1,-1});
sort(vctr.begin(),vctr.end());
findsize(1,-1,0);
eulertour(1,-1);
for (auto it : vctr) {
++borders[edges[it.s].s];
// printf("added %d\n",edges[it.s].s);
}
findborders(1,-1,0);
// for (int i = 1; i <= n; ++i) {
// printf("%d -> %d\n",in[i],out[i]);
// }
// for (int j = 1; j <= n; ++j) {
// printf("%d ",total[j]);
// }
// printf("\n");
for (int k = 1; k <= 19; ++k) {
for (int i = 1; i <= n; ++i) {
bl[i][k] = bl[bl[i][k-1]][k-1];
}
}
perstree[0] = build(1,n+1);
// for (int j = 1; j <= n; ++j) {
// printf("[%lld] ",query(perstree[0],1,n+1,1,in[j]).f);
// }
// printf("\n\n");
for (int i = 1; i <= m; ++i) {
// printf("%d %d : %d %d\n",edges[vctr[i].s].s,in[edges[vctr[i].s].s],edges[vctr[i].s].f,out[edges[vctr[i].s].s]);
perstree[i] = update(perstree[i-1],1,n+1,in[edges[vctr[i].s].s],vctr[i].f,1);
perstree[i] = update(perstree[i],1,n+1,out[edges[vctr[i].s].s],-vctr[i].f,-1);
for (int j = 1; j <= n; ++j) {
// printf("[%lld] ",query(perstree[i],1,n+1,1,in[j]).f);
}
// printf("\n\n");
}
// for (int i = 0; i <= m; ++i) {
// for (int j = 1; j <= n; ++j) {
// printf("%lld ",query(perstree[i],1,n+1,1,in[j]).f);
// }
// printf("\n");
// }
for (int qi = 0; qi < q; ++qi) {
int s, t, x;
long long y;
scanf("%d%d%d%lld",&s,&t,&x,&y);
int l = 0, r = m;
int lca = findlca(s,t);
// printf("\n%d %d lca: %d\n",s,t,lca);
while (true) {
if (l >= r)break;
int mid = (l+r+1)/2;
long long cost = path(mid,s,t,lca).f;
// printf("%d %lld\n",mid,cost);
if (cost <= y) {
l = mid;
} else {
r = mid-1;
}
}
// printf("%d !\n\n",l);
int coins = path(l,s,t,lca).s;
int totalcoins = tcoins(s,t,lca);
int pay = totalcoins-coins;
// printf("%d %d %d\n",coins,totalcoins,pay);
if (pay <= x) {
printf("%d\n",x-pay);
} else {
printf("-1\n");
}
}
return 0;
}
