text: #include <stdio.h>
  #include <stdlib.h>
  
  /* run this program using the console pauser or add your own getch, system("pause") or input loop */
  
  int main() 
  {
  	int m,n,i,j,k,l;
  	scanf("%d%d",&m,&n);
  	long long s1,s2,s3;
  	s1=1;
  	s2=1;
  	s3=1;
  	if(m<=n)
  		printf("1");
  	else if(n==0)
  		printf("1");
  	else{
  	for(i=1;i<=m;i++)
  		s1*=i;
  	for(j=1;j<=n;j++)
  		s2*=j;
  	for(k=1;k<=m-n;k++)
  		s3*=k;
  	
  	l=s1/(s2*s3);
  	printf("%d",l);}	
  	return 0;
  }