#include<stdio.h>
int main()
{
	int a;
	scanf("%d",&a);
	printf("%.2f",(a+a/100+a%100)*1.0/3);
	return 0;
}
/**************************************************************
	Problem: 1618
	User: admin
	Language: C
	Result: Accepted
	Time:10 ms
	Memory:1144 kb
****************************************************************/