import java.util.*;

public class Main{
	public static void main(String args[]){
		
		Scanner ob = new Scanner(System.in);
		int[] nums = new int[5];
		int C = 0;

		for(int i = 0; i < 5; i++){
			nums[i] = ob.nextInt();
		}

		for(int j = 0; j < 5; j++){
			if(nums[j] == 0){
				C = j + 1;
				break;
			}
		}

		System.out.println(C);
	}
}

/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