整数nの階乗を計算して表示する　メソッド

public class ren08_5
{
public static void main (String[] args) throws IOException
{
BufferedReader br =
new BufferedReader( new InputStreamReader(System.in));
System.out.print("整数を入力 > ");
int num = Integer.parseInt( br.readLine() );

System.out.println(num + "の階乗は " + factorial(num) + " です。");
}
public static int factorial(int n)//メソッド
{
int answer = 1;
for(int i=2; i<=n; i++){
answer *= i;
}
return answer;
}
}