#include <iostream>
#include <cmath>
using namespace std;
#define FORN(i,a,b) for (int i=a;i<=b;i++)
const int MAX=1000000;

pair<int,int> getPair(double n)
{
	int a,b;
	int c=0;
	double mingap=0.999;	//just under 1
	FORN(i,1,MAX)
	{
		int jlow=(int)(i/(n+mingap));
		int jhigh=(int) (i/(n-mingap));
		jlow=jlow<1?1:jlow;
		jhigh=jhigh>MAX?MAX:jhigh;
		FORN(j,jlow,jhigh)
		{	
			double temp=abs((double)i/j-n);
			if (temp<mingap) 
			{
				mingap=temp;
				a=i;
				b=j;
				break;
			}
		}
	}
	return make_pair(a,b);
}

int main()
{

	int casenum=1;
	
	double n;
	while(cin>>n && n!=0)
	{
		pair<int,int> p=getPair(n);
		if (casenum>1) cout<<endl;
		cout<<"Case "<<casenum++<<" is best approximated as "<<p.first<<"/"<<p.second<<endl;
	}

	return 0;
}