题解 | #截取字符串#

import java.io.*;

public class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        String str = bf.readLine();
        int num = Integer.parseInt(bf.readLine());
        StringBuilder sb = new StringBuilder();
        for (int i =0; i< num;i++){
            sb.append(str.charAt(i));
        }
        System.out.println(sb);
    }

}