#include<bits/stdc++.h>
using namespace std;

int main(){
    int in;
    vector<int> v;
    string G;
    char ans[]={"ABC"};

    while(cin >> in) v.push_back(in);
    for(int j=1;j<sizeof(ans);j++){
        for(int i=0;i<sizeof(ans)-j-1;i++){
            if(v[i]<v[i+1]) {
                swap(v[i],v[i+1]);
                swap(ans[i],ans[i+1]);
            }
        }
    }
    cout << ans << endl;

    return 0;
}