#include <iostream>
using namespace std;
struct P{char suit;int value;};
int main(void){
    struct P p[4];
    int i;
    p[0].suit='A',p[1].suit='B',p[2].suit='C';
    for(i=0;i<3;i++){
        cin>>p[i].value;
    }
    for(i=0;i<2;i++){
        if(p[i].value<p[i+1].value)swap(p[i],p[i+1]);
    }
    for(i=0;i<3;i++){
        cout<<p[i].suit<<endl;
    }
    return 0;
}