# include <iostream>
using namespace std;
double km2mile = 0.6214;
double ga2l = 3.875;

int main(){
	double ga, mi, eu_rate;
	cout << "The usage of oil (L) per 100 km: ";
	cin >> eu_rate;
	double us_rate =  km2mile * ga2l / eu_rate;
	cout << "Every gallon, the driver can drive " << us_rate << " mile(s)" << endl;
	return 0;
}