输入任意一个字符串，如：“abDEe23dJfd343dPOddfe4CdD5ccv!23rr”。取出该字符串中所有的字母。顺序不能改变！并把大写字母变成小写，小写字母变成大写！

package lovo.Linyoujia;

import java.util.Scanner;

public class Java {

@param args

public static void main(String[] args) {

TODO Auto-generated method stub

String bs = "asdfjvjadsffvaadfkfasaffdsasdffadsafafsafdadsfaafd";

int count = 0;

char[] charArray = bs.toCharArray();

for (int i = 0; i < bs.length() - 1; i++) {

if (charArray[i] == 'a' && charArray[i + 1] == 'f') {

count++;

}

}

System.out.println(count);