import java.util.Scanner;
publicclass Main {
publicstaticint f(int n ,int k){
int sum;
if ( k == 0 || k == n){
sum = 1;
}else{
sum = f(n-1, k)+f(n-1, k-1);//使用
}
return result;
}
publicstaticvoidmain(String[] args) {
Scanner in = new Scanner(System.in);
int k = in.nextInt();
int n = in.nextInt();
System.out.print(f(n, k));
in.close();
}
}