#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  int even = 0, odd = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] % 2 == 0) {
      even++;
    } else {
      odd++;
    }
  }
  for (int i = 0; i < n; i++) {
    if (even > odd) {
      if (a[i] % 2 == 1) {
        cout << i + 1;
        break;
      }
    } else {
      if (a[i] % 2 == 0) {
        cout << i + 1;
        break;
      }
    }
  }
}
