#include<bits/stdc++.h>
#define LL long long
const LL mod=1e9+7;
inline void read(LL &a)
{
	a=0;char c=getchar();
	while(c<'0'||c>'9')c=getchar();
	while(c>='0'&&c<='9')
	{
		a=(a<<1)+(a<<3)+c-'0';
		c=getchar();
	}
}
inline void write(LL a)
{
	if(a<0){putchar('-');a=-a;}
	if(a>9)write(a/10);
	putchar(a%10+'0');
}
LL n,m;
inline LL fast_pow(LL a,LL b)
{
	LL base=a,ans=1;
	while(b)
	{
		if(b&1)ans=ans*base%mod;
		base=base*base%mod;
		b>>=1;
	}
	return ans;
}
inline LL step(LL x)
{
	int ans=1;
	while(x)
	{
		ans=ans*x%mod;
		--x;
	}
	return ans;
}
inline LL C(LL m,LL n)
{
	return step(m)*fast_pow(step(n)*step((m-n))%mod,mod-2)%mod;
}
int main()
{
	read(m);read(n);
	write(C(m,n));
	return 0;
}