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

int main()
{
    pair<int, char> h[3];
    for(int i=0; i<3; ++i) cin>>h[i].first, h[i].second=i+'A';
    sort(h, h+3);
    reverse(h, h+3);
    for(auto& [x, y]: h) cout<<y<<endl;
}