#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define pb emplace_back
#define run ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0);
vector<int>id[100009];
signed main()
{
run;
int n,i,q;
cin>>n>>q;
vector<int>a(n,0),v;
for(i=0;i<n;i++)
{
cin>>a[i];
id[a[i]].pb(i+1);
}
while(q--)
{
int id1,l,r,k,x,y;
cin>>id1>>k>>l>>r;
auto it=lower_bound(id[id1].begin(),id[id1].end(),l);
if(it==id[id1].end())
{
cout<<-1<<endl;
continue;
}
x=it-id[id1].begin();
y=x+k-1;
if(y<id[id1].size())
{
if(id[id1][y]<=r)
{
cout<<id[id1][y]<<endl;
}
else
{
cout<<-1<<endl;
}
}
else
cout<<-1<<endl;
}
}
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