最难的问题

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

string a = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string b = "VWXYZABCDEFGHIJKLMNOPQRSTU";

int main(){

    string s;
    while (getline(cin, s)){
        for (char x : s){
            if (x == ' ')
                cout << " ";
            else
                cout << b[x - 'A'];
        }
        cout << endl;
    }

    //system("pause");
    return 0;
}