#include<iostream>
using namespace std;

int main()
{
    long long int a,b,c;
    while(cin>>a>>b>>c)
        if(a>=b && a>=c)
    {
        if(a>b+c)
        {
            cout<<"A"<<endl;
        }
        else if(b>c)
        {
            cout<<"B"<<endl;
        }
        else cout<<"C"<<endl;

    }
    else if (b>=a && b>=c)
    {
        if(b>a+c)
        {
            cout<<"B"<<endl;
        }
        else if(a>c)
        {
            cout<<"A"<<endl;
        }
        else cout<<"C"<<endl;
    }

    else if(c>=a && c>=b)
    {
        if(c>a+b)
        {
            cout<<"C"<<endl;
        }
        else if(a>b)
        {
            cout<<"A"<<endl;
        }
        else cout<<"B"<<endl;
    }

}