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