#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pill pair<int,ll>
#define mem(a, b) memset(a, b, sizeof(a))
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define int ll
#define name "test"
using namespace std;
const int N = 2e5 + 5;
const int LOG = 31 - __builtin_clz(N);
template <typename T1, typename T2> bool maxi(T1 &a, T2 b){if (a < b){a = b; return 1;} return 0;}
template <typename T1, typename T2> bool mini(T1 &a, T2 b){if (a > b){a = b; return 1;} return 0;}
struct item
{
int u, v, gold_coin;
long long silver_coin;
void input(){
cin >> u >> v >> gold_coin >> silver_coin;
}
};
struct FenwickTree{
int n;
int cnt[N];
long long val[N];
FenwickTree(){}
void reset(){
for (int i = 1; i <= n; i++)
val[i] = cnt[i] = 0;
}
void update(int idx, int x){
assert(idx > 0);
for (; idx <= n; idx += idx & -idx){
val[idx] += x;
cnt[idx] += (x < 0 ? -1 : 1);
}
}
pair<long long, int> get(int idx){
int s_cnt = 0;
long long sum = 0;
for (; idx; idx -= idx & -idx){
sum += val[idx];
s_cnt += cnt[idx];
}
return {sum, s_cnt};
}
} ft;
int n;
int m;
int q;
int st[N];
int ed[N];
int rep[N];
int ans[N];
int L[N], R[N];
int high[N];
int par[N][LOG + 1];
item query[N];
pii edges[N];
pii checkpoint[N];
vector<int> adj[N];
vector<int> query_list[N];
void load(){
cin.tie(0)->sync_with_stdio(0);
if (fopen(name".inp", "r")){
freopen(name".inp", "r", stdin);
freopen(name".out", "w", stdout);
}
}
void input(){
cin >> n >> m >> q;
for (int i = 1; i < n; i++){
int u, v; cin >> u >> v;
adj[u].push_back(i);
adj[v].push_back(i);
edges[i] = {u, v};
}
for (int i = 1; i <= m; i++){
cin >> checkpoint[i].fi >> checkpoint[i].se;
}
for (int i = 1; i <= q; i++){
query[i].input();
L[i] = 0;
R[i] = m;
}
}
void dfs_euler(int u, int pre){
static int cntDfs = 0;
st[u] = ++cntDfs;
for (int idx : adj[u]){
int v = edges[idx].fi + edges[idx].se - u;
if (v != pre){
rep[idx] = v;
par[v][0] = u;
high[v] = high[u] + 1;
dfs_euler(v, u);
}
}
ed[u] = cntDfs;
}
bool cmp(pii x, pii y){
return x.se < y.se;
}
int LCA(int u, int v){
if (high[u] < high[v]) swap(u, v);
for (int j = LOG; j >= 0; j--) if (high[par[u][j]] >= high[v]) u = par[u][j];
if (u == v) return u;
for (int j = LOG; j >= 0; j--) if (par[u][j] != par[v][j]){
u = par[u][j];
v = par[v][j];
}
return par[u][0];
}
void solve(){
mem(ans, -1);
dfs_euler(1, 0);
sort(checkpoint + 1, checkpoint + m + 1, cmp);
for (int j = 1; j <= LOG; j++)
for (int i = 1; i <= n; i++)
par[i][j] = par[par[i][j - 1]][j - 1];
high[0] = -1;
ft.n = n;
bool processing = 1;
while (processing){
processing = 0;
for (int i = 1; i <= q; i++){
if (L[i] <= R[i]){
processing = 1;
int m = (L[i] + R[i]) / 2;
query_list[m].push_back(i);
}
}
ft.reset();
for (int i = 0; i <= m; i++){
if (i && checkpoint[i].se <= (int)1e9){
ft.update(st[rep[checkpoint[i].fi]], checkpoint[i].se);
ft.update(ed[rep[checkpoint[i].fi]] + 1, -checkpoint[i].se);
}
for (int j : query_list[i]){
auto [u, v, gold_coin, silver_coin] = query[j];
int ancestor = LCA(u, v);
pair<long long, int> tmp1 = ft.get(st[u]);
pair<long long, int> tmp2 = ft.get(st[v]);
pair<long long, int> tmp3 = ft.get(st[ancestor]);
if (tmp1.fi + tmp2.fi - tmp3.fi * 2 <= silver_coin){
ans[j] = tmp1.se + tmp2.se - tmp3.se * 2;
L[j] = i + 1;
} else R[j] = i - 1;
}
query_list[i].clear();
}
}
ft.reset();
for (int i = 1; i <= m; i++){
ft.update(st[rep[checkpoint[i].fi]], checkpoint[i].se);
ft.update(ed[rep[checkpoint[i].fi]] + 1, -checkpoint[i].se);
}
for (int i = 1; i <= q; i++){
if (ans[i] == -1) cout << -1 << '\n';
else {
auto [u, v, gold_coin, silver_coin] = query[i];
int ancestor = LCA(u, v);
pair<long long, int> tmp1 = ft.get(st[u]);
pair<long long, int> tmp2 = ft.get(st[v]);
pair<long long, int> tmp3 = ft.get(st[ancestor]);
int tmp = tmp1.se + tmp2.se - tmp3.se * 2 - ans[i];
if (tmp <= gold_coin) cout << gold_coin - tmp << '\n';
else cout << -1 << '\n';
}
}
}
signed main(){
load();
input();
solve();
}
