#include <bits/stdc++.h>
using namespace std;
#define FOR(i, n) for(int i = 0; i < (n); i++)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())
typedef long long ll;

int main(int argc, char const *argv[]) {
	ios_base::sync_with_stdio(false);
	vector<pair<int, int> > v(3);
	FOR(i, 3) {
		int x;
		cin >> x;
		v[i] = {x, i};
	}
	sort(ALL(v));
	FOR(i, 3) cout << (char)('A'+v[i].second) << endl;
	return 0;
}