// SGU 222 -- Little Rooks
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.math.BigInteger;
class Solver {
BigInteger choose(int n, int k) {
BigInteger result = BigInteger.ONE;
for (int i = 0; i < k; ++ i) {
result = result.multiply(BigInteger.valueOf(n - i));
result = result.divide(BigInteger.valueOf(i + 1));
}
return result;
}
BigInteger square(BigInteger x) {
return x.multiply(x);
}
BigInteger factorial(int n) {
BigInteger result = BigInteger.ONE;
for (int i = 1; i <= n; ++ i) {
result = result.multiply(BigInteger.valueOf(i));
}
return result;
}
BigInteger solve(int n, int k) {
if (n < k) {
return BigInteger.ZERO;
}
return square(choose(n, k)).multiply(factorial(k));
}
void run(InputReader in, PrintWriter out) throws IOException {
int n = in.nextInt();
int k = in.nextInt();
out.println(solve(n, k));
out.close();
}
}
public class Solution {
public static void main(String args[]) {
try {
new Solver().run(new InputReader(System.in), new PrintWriter(System.out));
} catch (IOException e) {
}
}
}
class InputReader {
BufferedReader reader;
StringTokenizer tokenizer;
InputReader(InputStream in) {
reader = new BufferedReader(new InputStreamReader(in));
tokenizer = new StringTokenizer("");
}
String nextToken() throws IOException {
while (!tokenizer.hasMoreTokens()) {
tokenizer = new StringTokenizer(reader.readLine());
}
return tokenizer.nextToken();
}
int nextInt() throws IOException {
return Integer.parseInt(nextToken());
}
}