题解 | 小红的签到题

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        StringBuilder sb = new StringBuilder();
        sb.append('a').append('_');
        for (int i = 0; i < n - 2; i++) {
            sb.append('b');
        }
        System.out.println(sb.toString());
    }
}