// created by Dinh Manh Hung
// onepunchac168
// THPT CHUYEN HA TINH
// HA TINH, VIET NAM
#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("O3,unroll-loops,no-stack-protector")
//#pragma GCC target("sse4,avx2,fma")
#define task ""
#define ldb long double
#define pb push_back
#define fi first
#define se second
#define pc pop_back()
#define all(x) begin(x),end(x)
#define uniquev(v) v.resize(unique(all(v))-v.begin())
#define FOR(i,a,b) for (int i=a;i<=b;i++)
#define cntbit(v) __builtin_popcountll(v)
#define gcd(a,b) __gcd(a,b)
#define lcm(a,b) ((1LL*a*b)/__gcd(a,b))
#define mask(x) (1LL<<(x))
#define readbit(x,i) ((x>>i)&1)
#define ins insert
typedef long long ll;
typedef pair <ll,ll> ii;
typedef pair <ll,ii> iii;
typedef pair <ii,ii> iiii;
ll dx[]= {1,-1,0,0,1,-1,1,-1};
ll dy[]= {0,0,-1,1,1,-1,-1,1};
const ldb PI = acos (-1);
//const ll mod=978846151;
//const ll base=29;
const int maxn=1e6+5;
const int mod=1e9+7;
const char nl = '\n';
inline int ReadInt()
{
char co;
for (co = getchar(); co < '0' || co > '9'; co = getchar());
int xo = co - '0';
for (co = getchar(); co >= '0' && co <= '9'; co = getchar())
xo = xo * 10 + co - '0';
return xo;
}
void WriteInt(int xo)
{
if (xo > 9)
WriteInt(xo / 10);
putchar(xo % 10 + '0');
}
/* END OF TEMPLATE*/
// ================= Solution =================//
const int N=1e5+5;
ll n,m,k;
vector <ll> vt[N];
ll p[N],c[N];
vector <ll> opt;
struct Node {
int left,right;
ll val;
ll vala;
Node(int left,int right,ll val,ll vala){
this->left=left;
this->right=right;
this->val=val;
this->vala=vala;
}
Node(){
}
} T[N*24+5];
int ver[N];
vector <ll> tmp[N];
int Nnode=0;
int update(int oldnode,int l,int r,int u,ll val)
{
if (l==r)
{
Nnode++;
T[Nnode]=Node(0,0,val,val*opt[r-1]);
return Nnode;
}
int mid=(l+r)/2;
Nnode++;
int newnode=Nnode;
if (u<=mid)
{
T[newnode].left=update(T[oldnode].left,l,mid,u,val);
T[newnode].right=T[oldnode].right;
T[newnode].val=T[T[newnode].left].val+T[T[newnode].right].val;
T[newnode].vala=T[T[newnode].left].vala+T[T[newnode].right].vala;
}
else
{
T[newnode].right=update(T[oldnode].right,mid+1,r,u,val);
T[newnode].left=T[oldnode].left;
T[newnode].val=T[T[newnode].left].val+T[T[newnode].right].val;
T[newnode].vala=T[T[newnode].left].vala+T[T[newnode].right].vala;
}
return newnode;
}
ll query(int node,int l,int r,int u,int v)
{
if (l>v||r<u)
{
return 0;
}
if (l>=u&&r<=v)
{
return T[node].val;
}
int mid=(l+r)/2;
ll a1=query(T[node].left,l,mid,u,v);
ll a2=query(T[node].right,mid+1,r,u,v);
return a1+a2;
}
ll querya(int node,int l,int r,int u,int v)
{
if (l>v||r<u)
{
return 0;
}
if (l>=u&&r<=v)
{
return T[node].vala;
}
int mid=(l+r)/2;
ll a1=querya(T[node].left,l,mid,u,v);
ll a2=querya(T[node].right,mid+1,r,u,v);
return a1+a2;
}
map<ii,ll> mp;
ll cha[N][25];
ll sz[N];
void dfs(int u,int vv)
{
for (auto v:vt[u])
{
if (v==vv)
{
continue;
}
cha[v][0]=u;
sz[v]=sz[u]+1;
for (int i=1;i<=20;i++)
{
cha[v][i]=cha[cha[v][i-1]][i-1];
}
dfs(v,u);
}
}
void dfs1(int u,int vv)
{
ver[u]=ver[vv];
for (auto v:tmp[u])
{
ll aa=lower_bound(opt.begin(),opt.end(),v)-opt.begin()+1;
ll bb=query(ver[u],1,opt.size(),aa,aa);
ver[u]=update(ver[u],1,opt.size(),aa,bb+1);
}
for (auto v:vt[u])
{
if (v==vv)
{
continue;
}
dfs1(v,u);
}
}
ll lca(int u,int v)
{
if (sz[u]>sz[v]){swap(u,v);}
for (int i=20;i>=0;i--)
{
if (sz[v]-mask(i)>=sz[u])
{
v=cha[v][i];
}
}
if (u==v){return u;}
for (int i=20;i>=0;i--)
{
if (cha[u][i]!=cha[v][i])
{
u=cha[u][i];
v=cha[v][i];
}
}
if (u!=v)
{
u=cha[u][0];
v=cha[v][0];
}
return u;
}
ll ua[N],va[N];
void optmushnpr()
{
cin>>n>>m>>k;
T[0]=Node(0,0,0,0);
ver[0]=0;
for (int i=1;i<n;i++)
{
cin>>ua[i]>>va[i];
vt[ua[i]].pb(va[i]);
vt[va[i]].pb(ua[i]);
}
dfs(1,0);
for (int i=1;i<=m;i++)
{
cin>>p[i]>>c[i];
ll id=p[i];
if (sz[ua[id]]>sz[va[id]])
{
tmp[ua[id]].pb(c[i]);
}
else
{
tmp[va[id]].pb(c[i]);
}
opt.pb(c[i]);
}
sort (opt.begin(),opt.end());
uniquev(opt);
dfs1(1,0);
while (k--)
{
ll x,y,u,v;
cin>>u>>v>>x>>y;
ll left=1;ll right=opt.size();
ll parent=lca(u,v);
ll ans=opt.size();
ll sum=querya(ver[u],1,opt.size(),1,opt.size())+querya(ver[v],1,opt.size(),1,opt.size())-2*querya(ver[parent],1,opt.size(),1,opt.size());
while (left<=right)
{
ll mid=(left+right)/2;
ll a1=querya(ver[u],1,opt.size(),1,mid);
ll a2=querya(ver[v],1,opt.size(),1,mid);
ll a3=querya(ver[parent],1,opt.size(),1,mid);
if (a1+a2-2*a3>=y)
{
sum=a1+a2-2*a3;
ans=mid;
right=mid-1;
}
else left=mid+1;
}
ll ok=0;
if (ans!=0)
{
if (sum>y)
{
ll h=(sum-y)/opt[ans-1];
if (h*opt[ans-1]<sum-y)
{
h++;
}
ok=h;
}
}
ll a1=query(ver[u],1,opt.size(),ans+1,opt.size());
ll a2=query(ver[v],1,opt.size(),ans+1,opt.size());
ll a3=query(ver[parent],1,opt.size(),ans+1,opt.size());
ok+=a1+a2-2*a3;
if (ok<=x)
{
cout<<x-ok<<nl;
}
else cout<<-1<<nl;
}
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
if (fopen(task".inp","r")){
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);}
int t;
t=1;
//cin>>t;
while (t--){optmushnpr();}
}
// goodbye see ya
