#include <iostream>
using namespace std;
typedef long long LL;
int main(int argc, char* argv[])
{
	LL D;
	cin>>D;
	double d=D+(8*D)/100.0;
	if (d==(LL)d){
		cout<<(LL)d<<endl;
	}else{
		cout<<d<<endl;
	}
	return 0;
}