import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] a = new int[5];
		a[0] = sc.nextInt();
		a[1] = sc.nextInt();
		a[2] = sc.nextInt();
		a[3] = sc.nextInt();
		a[4] = sc.nextInt();
		int b = 0;
		for(int i=0; i<5; i++) {
			if(a[i]==0) {
				b = i+1;
			}
		}
		sc.close();
		System.out.println(b);
	}

}
/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