#include <iostream>
#include <string>

using namespace std;

void PrintMove(string a, string b, string c);
void DoTowers(string & src, string & dest, string & aux, int size);

int main() {
   int count;
   string towerA="A:", towerB="B:", towerC="C:";
   char c;

   cout << "Enter the number of disks" << endl;
   cin >> count;
   cout << endl;

   if (count > 26) {
      cout << "Sorry, too many disks" << endl;
   } else {
       for(c = char('a'+count-1) ; c >= 'a'; c--) {
          towerA += c;
       }

       PrintMove(towerA, towerB, towerC);
       DoTowers(towerA, towerC, towerB, count);
   }

   return 0;
}

void PrintRest(string a, string b) {
    if (a[0] == 'B') {
       cout << a << endl;
       cout << b << endl;
    } else {
       cout << b << endl;
       cout << a << endl;
    }

    return;
}

void PrintMove(string a, string b, string c) {
    cout << endl;

    if (a[0] == 'A') {
       cout << a << endl;
       PrintRest(b,c);
    } else if (b[0] == 'A') {
       cout << b << endl;
       PrintRest(a,c);
    } else {
       cout << c << endl;
       PrintRest(a,b);
    }
    return;
}

void MoveADisk(string & src, string & dest, string & aux) {
    // put the disk on dest
    dest +=  src.back();
    // remove it from src
    src = src.substr(0,src.size()-1);

    PrintMove(src, dest, aux);

    return;
}

void DoTowers(string & src, string & dest, string & aux, int size){
      
     if (size == 0) {
        cout << "Nothing to do " << endl;
        return;
     }
     if (size == 1) {
         MoveADisk(src, dest,aux);
     }  else {
         // move smaller stack to aux
         DoTowers(src, aux, dest, size-1);

         MoveADisk(src, dest,aux);

         // move smaller stack to dest
         DoTowers(aux, dest, src, size-1);
     }

     return;
}