#include <bits/stdc++.h>
#define dec double
using namespace std;
const int N = 505;

int n, n1, n2; dec c;
struct node{ int x, v; }a[N], a1[N], a2[N];
dec dp[N][N];

dec calc1(dec now, int i) { return (dec)(now*a1[i].v+abs(a1[i].x))/(c-a1[i].v); }
dec calc2(dec now, int i) { return (dec)(now*a2[i].v+abs(a2[i].x))/(c-a2[i].v); }

int main() {
    // g++ code.cpp -o code.exe -std=c++14 -O2 -fno-ms-extensions "-Wl,--stack=1000000000" -DLOCAL; ./code
    time_t stm = clock();

    #ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("ans.out", "w", stdout);
    #else
    // freopen("tiii.in", "r", stdin);
    // freopen("tiii.out", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    #endif

    int Case = 0;

    int T; cin >> T; while (T--) {
        n1 = n2 = 0; cin >> c >> n;
        for (int i = 1; i <= n; i++) cin >> a[i].x;
        for (int i = 1; i <= n; i++) cin >> a[i].v;
        sort(a+1, a+n+1, [](node lhs, node rhs) -> bool {
            return lhs.x < rhs.x;
        });
        for (int i = n; i >= 1; i--) {
            if (a[i].x < 0) {
                a1[++n1] = a[i];
            }
        }
        for (int i = 1; i <= n; i++) {
            if (a[i].x > 0) {
                a2[++n2] = a[i];
            }
        }
        // cout << calc1(0, 1) << '\n';
        for (int i = 0; i <= n1; i++) {
            for (int j = 0; j <= n2; j++) {
                dp[i][j] = 1e18;
            }
        }
        dp[0][0] = 0;

        for (int k = 0; k <= n; k++) {
            for (int i = 0; i <= n1; i++) {
                for (int j = 0; j <= n2; j++) {
                    if (i+j!=k) continue;

                    dec wl = 0;
                    for (int l = i+1; l <= n1; l++) {
                        wl = max(wl, calc1(dp[i][j], l));
                        // printf("[%d,%d]->[%d,%d] %.2lf: %.2lf,%d\n", i, j, l, j, calc1(dp[i][j], l), dp[i][j], l);
                        dp[l][j] = min(dp[l][j], dp[i][j]+wl+wl*(j+l<n));
                    }
                    dec wr = 0;
                    for (int r = j+1; r <= n2; r++) {
                        wr = max(wr, calc2(dp[i][j], r));
                        // printf("[%d,%d]->[%d,%d] %.2lf\n", i, j, i, r, calc2(dp[i][j], r));
                        dp[i][r] = min(dp[i][r], dp[i][j]+wr+wr*(i+r<n));
                    }
                }
            }
        }

        cout << "Case #" << (++Case) << ": ";
        cout << fixed << setprecision(10) << dp[n1][n2] << '\n';
    }

    cerr << "Exec Time: " << (double)(clock()-stm)/CLOCKS_PER_SEC << "s" << endl;
    return 0;
}