题解 | #统计大写字母个数#

import java.util.*;
import java.util.regex.*;

public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        while (scan.hasNext()) {
            String str = scan.nextLine();
            String result = "-1";
            for(int i=0;i<str.length();i++){
                String m = String.valueOf(str.charAt(i));
                String s = "[^"+m+"]";
                String y = str.replaceAll(s,"");
                if(y.length()==1){
                    result = m;
                    break;
                }
            }
            System.out.println(result);
        }
    }  
}