Problem1520--组合数

1520: 组合数

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Time Limit : 2.000 sec  Memory Limit : 128 MB

Submit

Description

Input

1000000000 0
1000000000 2
1000000000 500000000

Output

1
499999999500000000
1000000000000000000

Sample Input Copy

1000000000 0
1000000000 2
1000000000 500000000

Sample Output Copy

1
499999999500000000
1000000000000000000