#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>

using namespace std;

#define int long long
#define rep(i,n) for(int i = 0; i < (n); i++)
#define INF ((long long)1e18)
#define MOD ((int)1e9+7)
#define endl "\n"

#define yn(f) ((f)?"Yes":"No")
#define YN(f) ((f)?"YES":"NO")

#define MAX

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);
	
	int a[4], b, c, ans;
	
	cin>>a[0]>>a[1]>>a[2];
	
	
	if(a[0] > a[1] && a[0] > a[2]) {
		cout<<'A'<<endl;
	} 
	else if(a[1] > a[0] && a[1] > a[2]){
		cout<<'B'<<endl;
	} else {
		cout<<'C'<<endl;
	}
	
	return 0;
}
