12646

#include <iostream>

using namespace std;

int main()
{
int a,b,c;

while(cin>>a)
{
cin>>b>>c;

if(a==b &&b==c)
{
cout<<"*\n";
continue;
}

if(a!=b && a!=c)
{
cout<<"A\n";
continue;
}

if(b!=a && b!=c)
{
cout<<"B\n";
continue;
}
if(c!=b && a!=c)
{
cout<<"C\n";
continue;
}

}

return 0;
}