import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
    int e = sc.nextInt();
    if (a == 0) 
      System.out.println("1");
    if (b == 0) 
      System.out.println("2");
    if (c == 0) 
      System.out.println("3");
    if (d == 0) 
      System.out.println("4");
    if (e == 0) 
      System.out.println("5");
  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz