import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[] xs = {
                -1,
                sc.nextInt(),
                sc.nextInt(),
                sc.nextInt(),
                sc.nextInt(),
                sc.nextInt()
        };
        for (int i = 1; i < xs.length; i++) {
            if (xs[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