十进制转16进制

import java.util.Scanner;

public class Q3 {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        String s;
        while (cin.hasNextLine()) {
            s = cin.nextLine();
            long ans = toTen(s);
            System.out.println(ans);
        }
        cin.close();
    }

    public static long toTen(String s) {
        long ans = 0;
        int base = 1;

        for (int i = s.length() - 1; i >= 2; i --, base *= 16) {
            char c = s.charAt(i);
            switch (c){
                case '1':
                    ans += 1*base;
                    break;
                case '2':
                    ans += 2*base;
                    break;
                case '3':
                    ans += 3*base;
                    break;
                case '4':
                    ans += 4*base;
                    break;
                case '5':
                    ans += 5*base;
                    break;
                case '6':
                    ans += 6*base;
                    break;
                case '7':
                    ans += 7*base;
                    break;
                case '8':
                    ans += 8*base;
                    break;
                case '9':
                    ans += 9*base;
                    break;
                case 'a':
                case 'A':
                    ans += 10*base;
                    break;
                case 'b':
                case 'B':
                    ans += 11*base;
                    break;
                case 'c':
                case 'C':
                    ans += 12*base;
                    break;
                case 'd':
                case 'D':
                    ans += 13*base;
                    break;
                case 'e':
                case 'E':
                    ans += 14*base;
                    break;
                case 'f':
                case 'F':
                    ans += 15*base;
                    break;
            }
        }

        return ans;
    }
}