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lightoj 1050.cpp
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lightoj 1050.cpp
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// Created by ash_98
#include<bits/stdc++.h>
using namespace std;
#define mx 505
#define ll double
#define mod 1000000007
int ar[mx];
char ch[mx];
ll dp[mx][mx];
bool vis[mx][mx];
int n,m,k,ii;
ll func(int a,int b)
{
if(a==0 && b==0)return 1.00;
if(a==0)return 1.00;
if(b<=0)return 0.00;
if(vis[a][b])return dp[a][b];
vis[a][b]=true;
ll re=0.0;
re+=(ll)a*(func(a-1,b-1)/(ll)(a+b));
if(b>=2)re+=(ll)b*(func(a,b-2)/(ll)(a+b));
return dp[a][b]=re;
}
/*
ll dp[mx][mx][3];
bool vis[mx][mx][3];
ll func(int a,int b,int ti)
{
if(a+b==1)
{
if(b==1)return 1;
return 0;
}
if(vis[a][b][ti])return dp[a][b][ti];
vis[a][b][ti]=true;
ll re=0;
if(ti==0)
{
ll tem=((ll)b)/((ll)a+(ll)b);
if(b>0)re+=tem*func(a,b-1,1);
tem=((ll)a)/((ll)a+(ll)b);
if(a>0)re+=tem*func(a-1,b,1);
}
if(ti==1)
{
if(b>0)re+=func(a,b-1,0);
}
return dp[a][b][ti]=re;
}
*/
void solve()
{
int x,y;
scanf("%d%d",&x,&y);
ii++;
ll re=func(x,y);
printf("Case %d: %lf\n",ii,re);
}
int main()
{
int t=1;
scanf("%d",&t);
while(t--)
{
solve();
}
return 0;
}