public class Test {
static long fun(int n) {
if(n <= 1)
return 1;
else
return n*fun(n-1);
}
public static void main(String[] args) throws IOException {
BufferedReader din = new BufferedReader(
new InputStreamReader(System.in));
System.out.print("Enter an integer: ");
int jellen = Integer.parseInt(din.readLine());
long result = fun(jellen);
System.out.println(jellen + " != " + result);
}
}