?
package com.javarush.task.task15.task1531;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
/*
Факториал
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int input = Integer.parseInt(reader.readLine());
reader.close();
System.out.println(factorial(input));
}
public static String factorial(int n) {
//add your code here
if(n <=0) {
return "1";
}
else if(n<=150 && n>0){
ArrayList arr = new ArrayList();
BigInteger multy = new BigInteger("1");
for(int i = 0; i < n ; i++) {
arr.add(n - i);
BigInteger a =new BigInteger(String.valueOf(arr.get(i)));
multy = multy.multiplay(a);
}
return multy.toString();
}
return"";
}
}