package main

import (
	"fmt"
	"sort"
)

func main() {
	H := make([]int, 3)
	h := make([]int, 3)
	for i := 0; i < 3; i++ {
		fmt.Scan(&H[i])
	}
	copy(h, H)
	sort.Ints(H)
	// log.Println(H, h)
	for i := 2; i >= 0; i-- {
		switch H[i] {
		case h[0]:
			fmt.Println("A")
		case h[1]:
			fmt.Println("B")
		case h[2]:
			fmt.Println("C")
		}
	}
}