JAVA朴素解法

import java.util.*;
import java.io.*;
public class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String in;
        while((in = br.readLine())!=null){
            System.out.println(getOc(in));
        }
    }
    public static int getOc(String in){
        int res=0;
        for(int i=2;i<in.length();i++){
            int tmp=getOK(in.charAt(i));
            res=res*16+tmp;
        }
        return res;
    }
    public static int getOK(char ch){
        if(ch>='0'&&ch<='9'){
            return (int)ch - (int)('0');
        }else if(ch>='a'&&ch<='z'){
            return (int)ch - (int)('a')+10;
        }else{
            return (int)ch - (int)('A')+10;
        }
    }
}