#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  int k, r1 = 0, r2 = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] == 0) r1++;
    if (a[i] == 1) r2++;
  }
  for (int i = 0; i < n; i++) {
    if (a[i] == 0) r1--;
    if (a[i] == 1) r2--;
    if (r1 == 0 || r2 == 0) {
      k = i + 1;
      break;
    }
  }
  cout << k;
}
