#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<vector>
#include<algorithm>
typedef long long int ll;
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define REP(i,n) for (int i=0;i<(n);i++)
#define EREP(i,n) for (int i=1;i<=(n);i++)
const int MOD = 1000000007;
const int INF = 1000000;
     int A[3];
     priority_queue<int> H;
int main(){
    ios::sync_with_stdio(false);
    REP(i,3){cin>>A[i];H.push(A[i]);}
    REP(i,3){
        REP(j,3){
            if(H.top()==A[j]){
                if(j==0)cout<<"A"<<endl;
                if(j==1)cout<<"B"<<endl;
                if(j==2)cout<<"C"<<endl;
                H.pop();
                break;
            }
        }
    }

}