#define _USE_MATH_DEFINES	//M_PI(π),M_SQRT2(√2)
#include <iostream>			//std::cout, std::cin
#include <string>			//std::string,std::to_string(C++11)
#include <vector>			//std::vector
#include <valarray>			//std::valarray
#include <algorithm>		//std::sort
#include <time.h>			//localtime_s
#include <cstdlib>			//abs
#include <cmath>			//abs,std::pow,sqrt,sin,cos,round,floor,ceil
#include <fstream>			//std::ifstream,std::ofstream
#include <iomanip>			//std::setprecision,std::setw,std::setfill
#include <random>			//std::random(C++11)
#include <numeric>			//std::accumulate
#include <functional>		//std::greater

int main(void) {

	//test用
	//std::ifstream in("123.txt");
	//std::cin.rdbuf(in.rdbuf());

	unsigned long long N = 0, G = 0, V = 0;
	std::cin >> N >> G >> V;

	unsigned long long quot = (N / 5) *G / V;
	unsigned long long rema = (N / 5)* G % V;

	std::string S;
	for (int i = 0; i < 12; i++) {
		rema = rema * 10;
		S += std::to_string(rema / V);
		rema = rema % V;
	}

	std::cout << std::to_string(quot) + "." + S << std::endl;

}