#include<bits/stdc++.h> using namespace std; int a[1000]; int A,B,C; int main(){ int n;cin>>n; for(int i=0;i<n;i++){ cin>>a[i]; if(a[i]==1)A++; else if(a[i]==2)B++; else if(a[i]==3)C++; } if(A!=B&&A!=C&&B!=C){ if(A>B&&A>C)cout<<"A"; if(A<B&&B>C)cout<<"B"; if(C>B&&A<C)cout<<"C"; } if(A==B){ if(B>C)cout<<"NONE"; else cout<<"C"; } if(A==C){ if(B<C)cout<<"NONE"; else cout<<"B"; } if(B==C){ if(B>A)cout<<"NONE"; else cout<<"A"; } if(A==B&&B==C)cout<<"NONE"; return 0; }