1000! 中有多少个2

import java.math.BigInteger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

//求 1000！中2的个数

public class Num {
public static void main(String[] args) {
BigInteger bi = BigInteger.ONE;
for (int i = 2; i <= 1000; i++)
bi = bi.multiply(new BigInteger(i + ""));
String s = bi.toString();
Pattern p = Pattern.compile("2");
Matcher matcher = p.matcher(s);
String ss = "";
long wordNum = 0;
while (matcher.find()) {
ss += " " + matcher.group();
wordNum++;
}
System.out.println(bi.toString());
System.out.println("***********************");
System.out.println(ss);
System.out.println("*********************\n" + wordNum);
}

}