题解 | #牛牛的替换#

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 s1  = in.nextLine();
        String[] s2 = s1.split(" "); 
        String s = in.nextLine();
        String s3 = s.replace(s2[1],s2[2]);
        String s4 = s3.replace(s2[3],s2[4]);
        System.out.println(s4);

    }
}