#include <iostream>
#include <cstring>
using namespace std;
bool DFA(string s){
int state=0;
for(int i=0;i<s.size();i++){
//cout<<state<<" "<<s[i]<<endl;
switch(state){
case 0:switch(s[i]){
case 'a':state=1;break;
case 'b':state=2;break;
default :return false;
};break;
case 1:switch(s[i]){
case 'a':state=1;break;
case 'b':state=3;break;
default :return false;
};break;
case 2:switch(s[i]){
case 'a':state=1;break;
case 'b':state=2;break;
default :return false;
};break;
case 3:switch(s[i]){
case 'a':state=1;break;
case 'b':state=4;break;
default :return false;
};break;
case 4:switch(s[i]){
case 'a':state=1;break;
case 'b':state=2;break;
default :return false;
};break;
default :return false;
}
}
if(state==4)return true;
else return false;
}
int main()
{
string s;
cin>>s;
if(DFA(s)){cout<<"Accept"<<endl;}
else {cout<<"Error"<<endl;}
return 0;
}