#include <bits/stdc++.h>
using namespace std;
long long i, j, flag, c, k, x, z, n, m, a[300007];
int main() {
  cin >> n;
  long long lst0 = 0, lst1 = 1;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] == 0)
      lst0 = i + 1;
    else
      lst1 = i + 1;
  }
  cout << min(lst0, lst1) << endl;
  return 0;
}
