import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int x1 = sc.nextInt();
    int x2 = sc.nextInt();
    int x3 = sc.nextInt();
    int x4 = sc.nextInt();
    int x5 = sc.nextInt();
    
    if(x1==0)System.out.println(1);
    if(x2==0)System.out.println(2);
    if(x3==0)System.out.println(3);
    if(x4==0)System.out.println(4);
    if(x5==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