import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
			Scanner cin=new Scanner(System.in);
			int q[]=new int[100];
			for(int i=1;i<=5;++i)q[i]=cin.nextInt();
			for(int i=1;i<=5;++i) {
				if(q[i]==0) {
					System.out.println(i);
					break;
				}
			}
	}
}

/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