题解 | #计算某字符出现次数#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String baseStr = in.nextLine();
        String lowerStr = baseStr.toLowerCase();
        String charA = in.next();
        int len =  lowerStr.length() - lowerStr.replaceAll(charA.toLowerCase(), "").length();
        System.out.print(len);
    }
}