/*文件名:exam7_2.cpp*/
#include <stdio.h>
long fun(int x)
{
	int i;
	long f=1;
	for (i=2;i<=x;i++)
		f=f*i;
	return f;
}
main()
{
	int m,n;
	long c;
	do
	{
		printf("m,n:");
		scanf("%d%d",&m,&n);
	} while (m<=n);
    	c=fun(m)/(fun(n)*fun(m-n));
	printf("c=%ld\n",c);
}