1
3
5 3 4
 6
5
5 3 4 4 5
3
1 1 1
5
4 4 3 4 4
5
5 5 4 3 2
3
1 1 2
5
5 4 3 5 5
 1
3
10 1 5

1
 1
-1
2
2
3
1
 1

#include <bits/stdc++.h>
using namespace std;
int main(int argc, char** argv) {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    long long int mx = 0, mxi = -2;
    long long int a[n];
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
      if (mx < a[i] &&
          ((i - 1 >= 0 && a[i - 1] < a[i]) || (i + 1 < n && a[i] > a[i + 1]))) {
        mxi = i;
        mx = a[i];
      }
    }
    cout << (mxi + 1) << endl;
  }
}
