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::sync_with_stdio(false);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> aquriam(n);
    for (int i = 0; i < n; i++) cin >> aquriam[i];
    int max = aquriam[0];
    int idx = -1;
    for (int i = 1; i < n; i++) {
      if (aquriam[i] != aquriam[i - 1]) {
        if (aquriam[i] < aquriam[i - 1]) {
          idx = i;
        } else {
          idx = i + 1;
        }
      }
    }
    cout << idx << endl;
  }
  return 0;
}
