01 #include<iostream>
02 using namespace std;
03 int work(int N,int M)
04 {
05 int s=0;
06 if(M!=1)
07 s=(work(N-1,M-1)*work(N,M-1))/(work(N,M-1)-work(N-1,M-1));
08 else
09 return N;
10 return s;
11 }
12 main()
13 {
14 int M,N;
15 cin>>N>>M;
16 if(N%2==0)
17 if(M<=N/2)
18 cout<<"1/"<<work(N,M);
19 else
20 cout<<"1/"<<work(N,N-M+1);
21 if(N%2!=0)
22 if(M<=N/2+1)
23 cout<<"1/"<<work(N,M);
24 else
25 cout<<"1/"<<work(N,N-M+1);
26 //system("pause");
27 return 0;
28 }
0007
02 using namespace std;
03 int work(int N,int M)
04 {
05 int s=0;
06 if(M!=1)
07 s=(work(N-1,M-1)*work(N,M-1))/(work(N,M-1)-work(N-1,M-1));
08 else
09 return N;
10 return s;
11 }
12 main()
13 {
14 int M,N;
15 cin>>N>>M;
16 if(N%2==0)
17 if(M<=N/2)
18 cout<<"1/"<<work(N,M);
19 else
20 cout<<"1/"<<work(N,N-M+1);
21 if(N%2!=0)
22 if(M<=N/2+1)
23 cout<<"1/"<<work(N,M);
24 else
25 cout<<"1/"<<work(N,N-M+1);
26 //system("pause");
27 return 0;
28 }
0007