#include <stdio.h>

int main(){
	int n,j,d,s,np;

	scanf("%d",&n);
	j=n%10;
	d=(n/10)%10;
	s=(n/100)%10;
	np = n/1000*1000+j*100+d*10+s;
	printf("%d\n",np);

	return 0;
}