题解 | Letter Song ~ 致十年后的我们

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);
        char[] arr = in.next().toCharArray();
        String str = new String(arr, 0, 4);
        int year = Integer.parseInt(str);
        str = String.valueOf(year + 10);
        StringBuilder sb = new StringBuilder(str);
        for (int i = 4; i < 10; i++)
            sb.append(arr[i]);
        System.out.print(sb);
    }
}