import java.util.Scanner;
import java.lang.*;

public class Main{
 
	public static void main(String args[]){

      Scanner sc = new Scanner(System.in);
	int array[]  = new int[5];
	array[0] = sc.nextInt();
	array[1] = sc.nextInt();
	array[2] = sc.nextInt();
	array[3] = sc.nextInt();
	array[4] = sc.nextInt();



      for(int i = 0; i<5; i++){
      	if(array[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