import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

// ABC170-A
public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		List<Integer> x = new ArrayList<>();

		for (int i = 0; i < 5; i++) {
			x.add(sc.nextInt());
		}

		for (Integer i : x) {
			if (i == 0) {
				System.out.println(x.indexOf(i) + 1);
			}
		}

		sc.close();
	}
}

/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