#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
void MOUST(){
    ios_base::sync_with_stdio(0);
           cin.tie(0);
}
int main(){
    MOUST();

    int q;cin>>q;
    while(q--){
        ll n;cin>>n;
        ll a[n],k=0,p=-1;
        for(int i=0;i<n;i++){
            cin>>a[i];
            p=max(p,a[i]);
        }
       //cout<<k<<"   ";
        sort(a,a+n);

            for(int i=n-1;i>=0;i--){
                if(a[i]==p)
                    k++;
                else
                    break;
            }
            if(n-k+1==1)
                cout<<-1<<"\n";
            else
                cout<<n-k+1<<"\n";
    }

}