#include<bits/stdc++.h>
#define int __int128
#define fr(i,j,k) for(register int i=j;i<=k;++i)
#define rf(i,j,k) for(register int i=j;i>=k;--i)
#define foredge(i,j) for(register int i=head[j];i;i=e[i].nxt)
#define pb push_back
#define Times printf("Time:%.3lf\n",clock()/CLOCKS_PER_SEC)
using namespace std;
inline int read(){
	int x=0;
	bool f=0;
	char c=getchar();
	while(!isdigit(c)) f|=(c=='-'),c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return f?-x:x;
}
inline void write(int x){
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inline void writeln(int x){write(x); puts("");}
inline void writepl(int x){write(x); putchar(' ');}
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int randfind(int l,int r){return rnd()%(r-l+1)+l;}
//inline void init(){
//	int t=read();
//	while(t--) work();
//}
const int inf=1e18;
long long a,b;
int n,m;
int C[1010][1010];
inline void work(){
    n=a,m=b;
    if(m==0){
        writeln(1);
        return;
    }
    if(n<=1000){
        writeln(C[n][m]);
        return;
    }
    if(m>10){
        writeln(inf);
        return;
    }
    int ans=1,num1=n,num2=1;
    fr(i,1,m){
        ans=ans*num1/num2;
        --num1,++num2;
        if(ans>inf){
            writeln(inf);
            return;
        }
    }
    if(ans>inf) writeln(inf);
    else writeln(ans);
}
inline void init(){
    C[0][0]=1;
    int N=1e3;
    fr(i,1,N){
        C[i][0]=1;
        fr(j,1,i) C[i][j]=min(C[i-1][j]+C[i-1][j-1],inf);
    }
    while(scanf("%lld%lld",&a,&b)!=EOF) work();
}
signed main(){
	// freopen("input.in","r",stdin);
	// freopen("output.out","w",stdout);
    init();
    // printf("\nTIME:%.3lf",(double)clock()/CLOCKS_PER_SEC);
	return 0;
}