import java.util.Scanner;
public class TGMain {
    
    public static void main(String[] args){
        double G, V, N, b;
        int a;
        double ans;
        Scanner sc = new Scanner(System.in);
        
        N = sc.nextInt();
        G = sc.nextInt();
        V = sc.nextInt();
        a = (int)N/5;
        b = G*a;
        ans = b/V;
        System.out.println(ans);
    }
}