#define _USE_MATH_DEFINES

#include <iostream>
#include <iomanip>

#include <sstream>
#include <algorithm>
#include <cmath>

#include <string>
#include <vector>
//#include <valarray>


#include <queue>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>

#include<cassert>//assert();
#include <fstream>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
//#define mygc(c) (c)=getchar_unlocked()
/////////
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
/////////
using namespace::std;
/////////
int reader(char c[]){
	int i,s=0;
	for(;;){
		//mygc(i);
		//i = getchar_unlocked();
		i = getchar();
		if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF) break;
	}c[s++]=i;
	for(;;){
		//mygc(i);
		//i = getchar_unlocked();
		i = getchar();
		if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF) break;
		c[s++]=i;
	}c[s]='\0';return s;
}
/////////

void solve(){	
	ULL N,G,V;
	cin >> N >> G >> V;
	ULL mai,SUM;
	mai = N/5;
	SUM = mai * G;
	cout << SUM/V << ".";
	ULL ama = SUM%V;
	ULL M;
	M = ama;
	for(int i=0;M && i<25;++i){
		M *=10;
		cout << M/V;
		M = M%V;
	}
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	solve();
	
	return 0;
}