#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <cmath>
using namespace std;

typedef double T;
const T EPS = 1e-9;
const int MAXN = 600;

int n;
T len[MAXN];

T DP[MAXN];
double lis[MAXN];
int t;

const T PI = T(2.0) * acos(0.0);

T sqr(T x) {return x*x;}

T evalSum(T r2) {
	T aTot = 0;
	for(int i = 0; i < t; ++i) {
		aTot += asin(lis[i] / r2);
		if(aTot > PI + EPS) {
			break;
		}
	}
	return aTot;
}

T evalDiff(T r2) {
	T aTot = 0;
	aTot = -asin(lis[0] / r2);
	for(int i = 1; i < t; ++i) {
		aTot += asin(lis[i] / r2);
		if(aTot > 1e-3) {
			break;
		}
	}
	return aTot;
}
	
T mooHalf() {
	T r2 = lis[0];
	T del = 1e9;
	while(del > EPS) {
		if(evalDiff(r2 + del) < 0) {
			r2 += del;
		}
		del *= T(.5);
	}
	T r = r2 / T(2);
	T res = 0;
	for(int i = 0; i < t; ++i) {
		T s1 = lis[i] / T(2);
		T area = s1 * sqrt(sqr(r) - sqr(s1));
		if(i == 0) {
			res -= area;
		}
		else {
			res += area;
		}
	}
	return res;
}

T mooFull() {
	T r2 = lis[0];
	T del = 1e9;
	while(del > EPS) {
		if(evalSum(r2 + del) > PI + EPS) {
			r2 += del;
		}
		del *= T(.5);
	}
	T r = r2 / T(2);
	T res = 0;
	for(int i = 0; i < t; ++i) {
		T s1 = lis[i] / T(2);
		res += s1 * sqrt(sqr(r) - sqr(s1));
	}
	return res;
}

T maxArea(int l, int r, double goal) {
	if(r - l <= 2) return 0;
	t = 0;
	for(int i = l; i < r; ++i) {
		lis[t++] = len[i];
	}
	sort(lis, lis + t);
	for(int i = 0; i < t - 1 - i; ++i) {
		swap(lis[i], lis[t - 1 - i]);
	}
	T s = 0;
	for(int i = 1; i < t; ++i) {
		s += lis[i];
	}
	if(s < lis[0] + EPS) {
		return 0;
	}
	s += lis[0];
	T rad = s / PI / T(2.0);
	T maxEstimate = rad * rad * PI;
//printf("%lf %lf\n", maxEstimate, goal);
	if(maxEstimate < goal - EPS) return 0;

	T res = 0;
	if(evalDiff(lis[0]) < EPS) {
		res = mooHalf();
	}
	else {
		res = mooFull();
	}
//if(res > maxEstimate) printf("%lf %lf %lf\n", res, maxEstimate, s);
	return res;
}

int main() {
	int ct = 0;
	scanf("%d", &n);
	while(n) {
		ct++;
		for(int i = 0; i < n; ++i) {
			scanf("%lf", &len[i]);
		}
//printf("%d\n", n);
//printf("%lf\n", maxArea(0, n)); return 0;
		DP[0] = 0;
		for(int i = 1; i <= n; ++i) {
			DP[i] = 0;
			for(int j = 0; j < i; ++j) {
 				double a = maxArea(j, i, DP[i] - DP[j]);
				DP[i] = max(DP[i], DP[j] + a);
			}
		}
		printf("Case %d: %0.10lf\n", ct, DP[n]);
		scanf("%d", &n);
	}
	return 0;
}