#include
int solve(int n, int m)/*调用时n=7，m=4*/
{
int i, sum;
if (m == 1)
return 1;
sum = 0;
for (i = 1; i < n; i++)
sum += solve(i, m - 1);
return sum;/*sum=1+1+3+4+5+6*/
}
int main()
{
int n, m;
scanf("%d %d", &n, &m);/*输入n和m的值*/
printf("%d\n", solve(n, m)); /*输出solve函数的返回值*/
return 0;
}