import java.util.*;
import java.math.BigDecimal;

public class Exercise117{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    BigDecimal n = new BigDecimal(sc.next());
    BigDecimal g = new BigDecimal(sc.next());
    BigDecimal v = new BigDecimal(sc.next());
    BigDecimal sum = n.divide(BigDecimal.valueOf(5), 0, BigDecimal.ROUND_FLOOR).multiply(g);
    System.out.println(sum.divide(v, 14, BigDecimal.ROUND_FLOOR));
  }
}