import java.util.Scanner;

public class Main
{

	public static void main(String args[])
	{

		int[] x = new int[5];

		Scanner sc = new Scanner(System.in);

		x[0] = sc.nextInt();
		x[1] = sc.nextInt();
		x[2] = sc.nextInt();
		x[3] = sc.nextInt();
		x[4] = sc.nextInt();

		sc.close();

		for(int i = 0; i < 5; i++)
		{
			if(x[i] != (i + 1))
			{
				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