#include<iostream>
#include<cstdio>

using namespace std;

int main(){

	long long N,G,V;

	cin>>N>>G>>V;

	long long tmp=(N/5)*G;
	long long ans1=tmp/V;
	cout<<ans1<<".";
	long long ans2=((double)(tmp%V)/(double)V)*10000000000000;
	int keta=0;
	tmp=ans2;
	if(tmp==0) keta=1;
	while(tmp!=0){
		keta++;
		tmp/=10;
	}
	for(int i=0;i<13-keta;i++) cout<<"0";
	cout<<ans2<<endl;
}