#include <iostream>

using namespace std;

int main(){
long long int Strr[3];

while(cin>>Strr[0]>>Strr[1]>>Strr[2]){
char Strr1[3]={'A','B','C'};
int temp,counts=3;
char temp1;
for(int l=3;l>0;l--)
{
for(int i=0;i<2;i++)
{
if(Strr[i+1]<Strr[i])
{
temp=Strr[i];
temp1=Strr1[i];
Strr[i]=Strr[i+1];
Strr1[i]=Strr1[i+1];
Strr[i+1]=temp;
Strr1[i+1]=temp1;
}
}
}

int sum=Strr[2]-Strr[1]-Strr[0];

if(sum>0)
cout<<Strr1[2]<<endl;
else
cout<<Strr1[1]<<endl;

}

}