题解 | 小红的大小写字母

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 小红的大小写字母
		 Scanner sc = new Scanner(System.in);
//		 输入
	    int n = sc.nextInt();
	    int k = sc.nextInt();
	    String s = sc.next();
	    
	    int da = 0;//大写字母
	    int xiao = 0;//小写字母
	    
//	   	遍历字符串，统计大小写字母
	    for (int i = 0; i < s.length(); i++) {
			char a = s.charAt(i);
			if (a >='A' && a<= 'Z') {
				da++;
			} else {
				xiao++;
			}
		}
        int huan = Math.min(k, xiao); 
        int shengyu = k - huan;     
        int ans = da + huan - (shengyu % 2);
        
        System.out.println(ans);
        
        sc.close();

	}

}