import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
 
		Scanner sc = new Scanner(System.in);
		
		int [] x= {0,1,2,3,4,5};
		
		for(int i=1; i<=5; i++) {
			x[i]=sc.nextInt();
		}
		
		for(int i=1; i<=5; i++) {
			if(x[i]==0) {
				System.out.println(i);
			}
		}
		
 
	}
 
}

/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