import java.util.*;
public 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();
          	if( num[i] != (i+1) ){
              System.out.println( (i+1) );
            }
		}
		//System.out.println(ans);    	
	}
}
/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