CROSBLK.cpp

#include<bits/stdc++.h>
#define int          long long int 
#define pb           push_back
using namespace std;


void solve(){

    int n;
    cin>>n;
    vector<int>a(n);
    for(int i=0;i<n;i++){
        cin>>a[i];
    }
    int start=a[0];
    for(int i=1;i<n;i++){
        if(a[i]>start){
            cout<<-1<<endl;
            return;
        }
    }
    stack<int>s;
    for(int i=1;i<n;i++){
        while(s.size() and s.top()<=a[i]){
            s.pop();
        }
        s.push(a[i]);
    }
    int ans=0;
    while(!s.empty()){
        ans++;
        s.pop();
    }
    cout<<ans<<endl;
}
signed main(){
 ios_base::sync_with_stdio(false);
 cin.tie(0);cout.tie(0);

 int t;
 cin>>t;

 while(t--)
 {
  solve();
 }
 
 return 0;
}