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() {
  long long int t, n, x = 0, m, i, p = 1;
  cin >> t;
  while (t--) {
    p = 1;
    x = 0;
    cin >> n;
    long long int a[n + 2];
    for (i = 0; i < n; i++) cin >> a[i];
    m = a[0];
    a[n] = 1000000000;
    for (i = 1; i < n; i++) {
      if (m == a[i]) p++;
      if ((a[i] >= m) && (a[i] > a[i - 1]) || (a[i] > a[i + 1])) x = i;
    }
    if (p == n)
      cout << -1 << endl;
    else
      cout << x + 1 << endl;
  }
  return 0;
}
