#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"<<"\n";
else if(b>c)
cout<<"B"<<"\n";
else
cout<<"C"<<"\n";
}
else if(b>a&&b>c)
{
if(b>(a+c))
cout<<"B"<<"\n";
else if(a>c)
cout<<"A"<<"\n";
else
cout<<"C"<<"\n";
}
else if(c>a&&c>b)
{
if(c>(b+a))
cout<<"C"<<"\n";
else if(b>a)
cout<<"B"<<"\n";
else
cout<<"A"<<"\n";
}
}
return 0;
}