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 t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int a[n];
    int max = 0, q = 1, p = 0, z = 0;
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] > max) {
        max = a[i];
        p = i + 1;
        z = p;
        q = 1;
      } else if (a[i] == max) {
        q++;
        p++;
      }
    }
    if (p == n) {
      p = z;
    }
    if (q == n) {
      p = -1;
    }
    cout << p << endl;
  }
  return 0;
}
