C :

#include<stdio.h>

int main()
{
	int n,x;
	double s;
	while(scanf("%d",&n)!=EOF,n)
	{
		if(n<=4)
		{
			printf("10\n");
			continue;
		}
		s=n/8*18;
		x=n%8;
		if(!x)
			printf("%.lf\n",s);
		else if(x>=5)
		{
			s+=10+2*(x-4);
			printf("%.lf\n",s);
		}
		else
		{
			s+=2.4*x;
			printf("%.1lf\n",s);
		}
	}
	return 0;
}

C++ :

#include<stdio.h>

int main()
{
	int n,x;
	double s;
	while(scanf("%d",&n)!=EOF,n)
	{
		if(n<=4)
		{
			printf("10\n");
			continue;
		}
		s=n/8*18;
		x=n%8;
		if(!x)
			printf("%.lf\n",s);
		else if(x>=5)
		{
			s+=10+2*(x-4);
			printf("%.lf\n",s);
		}
		else
		{
			s+=2.4*x;
			printf("%.1lf\n",s);
		}
	}
	return 0;
}

Java :

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


class Main {

	private static Scanner scan=new Scanner(System.in);
	public static void main(String[] args) {
        boolean flag=true;
		List<Double> list=new ArrayList<Double>();
		while(flag)
		{
			Double value;
			int n=scan.nextInt();
			if(n==0)
			{
				flag=false;
				break;
			}
			else
			{
				if(n<=4)
				{
					value=10.00;
				}
				else if(n<=8)
				{
					value=(double) (10+(n-4)*2);
				}
				else
				{
					value=(double) (18*(n/8));
					if(n%8>4)
					{
						value=value+10+(n%8-4)*2;
					}
					else
					{
						value=value+(n%8)*2.4;
					}
				}
				list.add(value);
			}
		}
		for (Double s : list) 
		{
			double ss=(double)s;
			if(ss-(int)ss==0)
			{
				System.out.println((int)ss);
			}
			else 
			{
				DecimalFormat df = new DecimalFormat("0.0");
				System.out.println(df.format(ss));
			}
		}
    }
}