#include <stdio.h>

int main () {
  int n = 0;
  int a = 0;
  
  int res = 0;
  
  int is_ok = 0;
  
  res = scanf("%d", &n);
  while (n > 0) {
    res = scanf("%d", &a);
    if (a < 2) {
      is_ok++;
    }
    n--;
  }
  
  if (is_ok > 0) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  
  return 0;
}