#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define mset(arr,x) memset(arr,x,sizeof(arr))
#define rep(i,s,e) for(i=s;i<=e;i++)
#define rrep(i,s,e) for(i=s;i>=e;i--)

ll dp[4010][4010];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    ll N, i, j, T, M, ppll;
    string st;

    cin >> T;
    rep(ppll, 1, T)
    {
       mset(dp, 0);

       cin >> N >> M;
       rep(i, 1, N)
       {
           dp[i][0] = 1;
       }

       rep(i, 1, N)
       {
           rep(j, 1, i-1)
           {
               if( i!=j )
               {
                   dp[i][j] = dp[i-1][j] + dp[i][j-1];
               }
           }
       }

       double anss = (double)dp[N][M];
       ll val = N+M;

       rrep(i, M, 1)
       {
           double opop = (double)( ((double)i)/val );
           anss = ( anss * opop );
           val--;
       }

       cout << "Case #" << ppll << ": " << setprecision(12) << anss << endl;
    }

    return 0;
}