// 356. Extrasensory Perception
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;
import java.util.Arrays;
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 Solver {
void run(InputReader in, PrintWriter out) throws IOException {
int k = in.nextInt();
int n = in.nextInt();
BigInteger[][] binom = new BigInteger[n + 1][n + 1];
for (int i = 0; i <= n; ++ i) {
Arrays.fill(binom[i], BigInteger.ZERO);
binom[i][0] = BigInteger.ONE;
for (int j = 1; j <= i; ++ j) {
binom[i][j] = binom[i - 1][j].add(binom[i - 1][j - 1]);
}
}
BigInteger[] derangement = new BigInteger[Math.max(n + 1, 3)];
derangement[1] = BigInteger.ZERO;
derangement[0] = derangement[2] = BigInteger.ONE;
for (int i = 3; i <= n; ++ i) {
derangement[i] = BigInteger.valueOf(i - 1).multiply(derangement[i - 1].add(derangement[i - 2]));
}
BigInteger ways = derangement[n - k].multiply(binom[n][k]);
BigInteger total = BigInteger.ONE;
for (int i = 1; i <= n; ++ i) {
total = total.multiply(BigInteger.valueOf(i));
}
if (true) {
BigInteger d = ways.gcd(total);
ways = ways.divide(d);
total = total.divide(d);
}
if (ways.equals(BigInteger.ZERO)) {
out.println(ways);
} else {
out.println(String.format("%d/%d", ways, total));
}
out.close();
}
}
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());
}
}