import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		
		
		

		Scanner scanner = new Scanner(System.in);
		String[] ar = scanner.nextLine().split(" ");
		
		

		for(int i=0; i<ar.length; i++) {
			if (Integer.parseInt(ar[i]) == 0) {
				System.out.println(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