#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v, w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;
int INF = INT_MAX / 2;

int main() {
    int T; cin >> T;
    for (int t = 1; t <= T; t++) {
        int x, b; scanf("%d%d", &x, &b);
        double e = 0;
        for (int S = 0; S < (1 << (b - 1)); S++) {
            int cnt = 1; double p = 1;
            for (int i = 0; i < b - 1; i++) {
                double q = min(1.0, (double)cnt / x);
                if (S & (1 << i)) {
                    p *= 1 - q;
                    cnt++;
                }
                else p *= q;
            }
            e += p * cnt;
        }
        printf("Case #%d: %.3f\n", t, e * (x + 1) / 2);
    }
}