#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <iomanip>
#include <random>
#include <chrono>
#include <queue>
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
#define INF 1000000000
#define MOD 1000000007
#define EPS 0.00000001

int main (){
    int mx = -INF;
    int idx = 0;
    for(int i=0; i<3; i++){
        int r; cin >> r;
        if(r>mx){
            mx = r;
            idx = i;
        }
    }
    
    string S = "ABC";
    cout << S[idx] << endl;
    return 0;
}


