#include <iostream>
using namespace std;
long fac(int n)//求n的阶乘
{
int i,c=1;
for(i=1;i<=n;i++)
c=c*i;
return c;
}
int main()
{
double C,n,m,a;
cout<<"请输入m与n的值:";
cin>>m>>n;
if (m<n)
{
a=m;
m=n;
n=a;
}
C=fac(m)/(fac(n)*fac(m-n));
cout<<C<<endl;
return 0;

long fac(int n)//求n的阶乘
{
int i,c=1;
for(i=1;i<=n;i++)
c=c*i;
return c;
}
int main()
{
double C,n,m,a;
cout<<"请输入m与n的值:";
cin>>m>>n;
if (m<n)
{
a=m;
m=n;
n=a;
}
C=fac(m)/(fac(n)*fac(m-n));
cout<<C<<endl;
return 0;