无聊的牛牛和羊羊

	/***



	*这个题完全就是数学题了吧。。。



	*/



	



	importjava.util.Scanner;



	 



	publicclassMain {



	    publicstaticvoidmain(String[] args) {



	        Scanner scanner = newScanner(System.in);



	        while(scanner.hasNext()) {



	            intn = scanner.nextInt();



	            intm = scanner.nextInt();



	            float[] dp = newfloat[m + 1];



	            if(m == 0) {



	                System.out.println(0);



	                return;



	            }



	            if(m == 1) {



	                floatres = (n + 1) / 2.0f;  //和下面的不同，此处已知m=1



	                String r = String.format("%.1f", res);



	                System.out.println(r);



	                return;



	            }



	            dp[1] = (n+ m) / 2.0f;  //注意此处



	            for(inti = 2; i <= m; i++) {



	                dp[i] = p1(m + n-i, i) + p2(m + n -i, i) * (dp[i-1] + 1) + p3(m + n -i, i) * (dp[i-2] + 1);



	            }



	            String r = String.format("%.1f", dp[m]);



	            System.out.println(r);



	        }



	 



	    }



	 



	    privatestaticfloatp1(intn, intm) {



	        intc1 = n * (n-1) / 2;



	        ints = (n + m) * (n + m -1) / 2;



	        floatres = c1 * 1.0f / (s - c1);



	        returnres;



	    }



	 



	    privatestaticfloatp2(intn, intm) {



	        intc1 = n * (n-1) / 2;



	        intc2 = n * m;



	        ints = (n + m) * (n + m -1) / 2;



	        floatres = c2 * 1.0f / (s - c1);



	        returnres;



	    }



	 



	    privatestaticfloatp3(intn, intm) {



	        intc1 = n * (n-1) / 2;



	        intc3 = m * (m  -1) / 2;



	        ints = (n + m) * (n + m -1) / 2;



	        floatres = c3 * 1.0f / (s - c1);



	        returnres;



	    }



	 



	}