import java.util.*;
public class Main{

     public static void main(String []args){
        int arr[]=new int[5];
        Scanner sc=new Scanner(System.in);
       for(int i=0;i<5;i++)
          arr[i]=sc.nextInt();
    for(int i=0;i<5;i++)
    if(arr[i]==0)
       System.out.print(i+1);
         
     }
}
/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