import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.BigDecimal;

class Main
{
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		int[] num = new int[5];
		
		for(int i = 0; i < 5; i++)
		{
			num[i] = sc.nextInt();
		}
		
		for(int i = 0; i < 5; i++)
		{
			if(num[i] == 0)
			{
				System.out.println(i + 1);
				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