#include <cstdio>

 #include <iostream>

 #include <algorithm>

 #include <cstring>

 #include <map>

 #include <stack>

 #include <string>

 using namespace std;

 char q[][], op[], tmp[];

 int qh, qt, last[];

 map<string, int> pos;

 void op1(char *s) { reverse(s, s + );}

 void op2(char *s, bool op) {

     if (op) {

         rotate(s, s + , s + );

         rotate(s + , s + , s + );

     } else {

         rotate(s, s + , s + );

         rotate(s + , s + , s + );

     }

 }

 void op3(char *s, bool op) {

     char t;

     if (op) {

         t = s[];

         s[] = s[];

         s[] = s[];

         s[] = s[];

         s[] = t;

     } else {

         t = s[];

         s[] = s[];

         s[] = s[];

         s[] = s[];

         s[] = t;

     }

 }

 void PRE() {

     for (int i = ; i < ; i++) tmp[i] = i + '';

     tmp[] = ;

     pos.clear();

     qh = qt = ;

     strcpy(q[qt], tmp);

     pos[tmp] = qt;

     last[qt] = -;

     op[qt++] = ;

     while (qh < qt) {

         strcpy(tmp, q[qh]);

         op1(tmp);

         if (pos.find(tmp) == pos.end()) {

             strcpy(q[qt], tmp);

             pos[tmp] = qt;

             last[qt] = qh;

             op[qt++] = 'A';

         }

         strcpy(tmp, q[qh]);

         op2(tmp, true);

         if (pos.find(tmp) == pos.end()) {

             strcpy(q[qt], tmp);

             pos[tmp] = qt;

             last[qt] = qh;

             op[qt++] = 'B';

         }

         strcpy(tmp, q[qh]);

         op3(tmp, true);

         if (pos.find(tmp) == pos.end()) {

             strcpy(q[qt], tmp);

             pos[tmp] = qt;

             last[qt] = qh;

             op[qt++] = 'C';

         }

         qh++;

     }

 }

 int main() {

 //    freopen("in", "r", stdin);

     PRE();

     char bg[], ed[], con[];

     while (cin >> bg >> ed) {

         for (int i = ; i < ; i++) {

             int t = ;

             while (bg[i] != ed[t]) t++;

             con[t] = i + '';

         }

         con[] = ;

         int cur = pos[con];

         stack<char> path;

         while (!path.empty()) path.pop();

         while (cur) {

             path.push(op[cur]);

             cur = last[cur];

         }

         while (!path.empty()) {

             putchar(path.top());

             path.pop();

         }

         puts("");

     }

     return ;

 }