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() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int Tests;
  cin >> Tests;
  for (int Test = 1; Test <= Tests; ++Test) {
    int n, ok = 0;
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; ++i) {
      cin >> arr[i];
      if (i > 0)
        if (arr[i] != arr[i - 1]) ok = 1;
    }
    if (ok)
      cout << 1 + (int)(max_element(arr, arr + n) - arr) << '\n';
    else
      cout << "-1\n";
  }
  return 0;
}
