import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int[] ary = new int[5];
        for(int i=0; i<5; i++){
            ary[i] = Integer.parseInt(sc.next());
        }

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