Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	a := getNextInt(scanner)
	b := getNextInt(scanner)
	c := getNextInt(scanner)
	if a == most(a, b, c) {
		fmt.Fprintln(writer, "A")
		return
	}
	if b == most(a, b, c) {
		fmt.Fprintln(writer, "B")
		return
	}
	fmt.Fprintln(writer, "C")
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}
func most(a, b, c int) int {
	return max(a, max(b, c))
}

C++: //include
//------------------------------------------
#include <bits/stdc++.h>
using namespace std;

//typedef
//------------------------------------------
typedef long long LL;
typedef vector<LL> VL;
typedef vector<VL> VVL;
typedef vector<string> VS;
typedef pair<LL, LL> PLL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);
const int MOD = 1000000007;

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

//main code

int main(int argc, char const* argv[])
{
	int a,b,c;
	cin >> a >> b >> c;
	int m = max(a,max(b,c));
	if (m == a) {
		cout << "A" << endl;
	}
	else if (m == b) {
		cout << "B" << endl;
	}
	else {
		cout << "C" << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
template<typename T1,typename T2> bool chmin(T1 &a,T2 b){if(a<=b)return 0; a=b; return 1;}
template<typename T1,typename T2> bool chmax(T1 &a,T2 b){if(a>=b)return 0; a=b; return 1;}


signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);

    int a,b,c;
    cin>>a>>b>>c;
    int ma = 0;
    char ans;
    if(chmax(ma,a))ans='A';
    if(chmax(ma,b))ans='B';
    if(chmax(ma,c))ans='C';
    cout << ans << endl;
}

C++: //↓template↓

#include "bits/stdc++.h"
using namespace std;
#define Would
#define you
#define all(n)  n.begin(),n.end()
const long long INF = 1e18;
const long long MOD = 1e9 + 7;
const double pi = acos(-1);
const int SIZE = 1 << 17;
int dx[] = { 1,0 }, dy[] = { 0,1 }, alp[30];
long long fac[200005], finv[200005], inv[200005];
vector<long long>dij;
struct edge { long long to, cost; };
vector<vector<edge> >G;

long long mod_pow(long long a, long long b) {
	long long res = 1, mul = a;
	for (int i = 0; i < 31; ++i) {
		if (b >> i & 1) {
			res *= mul;
			res %= MOD;
		}
		mul = (mul * mul) % MOD;
	}

	return res;
}

void addedge(int from, int to, int cost) {
	G[from].push_back({ to,cost });
	G[to].push_back({ from,cost });
}

//↑template↑

char out = 'C';
int main() {
	int a, b, c;
	cin >> a >> b >> c;
	int ans = max({ a,b,c });

	if (ans == a) { out = 'A'; }
	else if (ans = b) { out = 'B'; }

	cout << out << endl;
}