ncr by mod

#include<bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef unsigned long long ull;
typedef pair<ll,ll>pll;
typedef pair<ll,pair<ll,ll>>plll;
#define bismillah; (ios_base:: sync_with_stdio(false),cin.tie(NULL));
#define vll(v) v.begin(),v.end()
#define all(x) x.rbegin(),x.rend()
#define min3(a, b, c)   min(a, min(b, c))
#define max3(a, b, c)   max(a, max(b, c))
#define ff first
#define ss second
#define in  freopen("input.txt", "r", stdin)
#define out  freopen("output.txt", "w", stdout)
#define minheap int,vector<int>,greater<int>
#define pb push_back
#define eb emplace_back
#define ischar(x)  (('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z'))
#define isvowel(ch) ((ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u')||(ch=='A'|| ch=='E' || ch=='I'|| ch=='O'|| ch=='U'))
#define bug cout<<"BUG"<<endl;
const int Max = 2e5 ;
const int Mod = 1e9 + 7;
ll fact[Max+10];
long long bigmod(long long b,long long p,ll mod)
{

    if(p==0)return 1ll;

    ll x=bigmod(b,p/2,mod);

    x=(x*x)%mod;

    if(p&1)x=(x*b)%mod;

    return x;
}


void init()
{
    fact[0]=1;

    for(ll i=1; i<=Max; i++)
    {
        fact[i]=(i*fact[i-1])%Mod;
    }
}

ll NCR(ll n,ll r)
{
    return (fact[n]*bigmod((fact[r]*fact[n-r])%Mod,Mod-2,Mod))%Mod;

}
int main()
{

    bismillah;


    cin>>nn>>rr;

     ll ans=NCR(nn,rr);


       cout<<ans<<endl;


}