#include<stdio.h>
int main()
{
	int a,b;
	scanf("%d",&a);
	printf("%d",a-(a%10*1000+a/10%10*100+a/100%10*10+a/1000));
	return 0;
}
/**************************************************************
	Problem: 1702
	User: admin
	Language: C
	Result: Accepted
	Time:10 ms
	Memory:1144 kb
****************************************************************/