let a:[Int] = readLine()!.split(separator: " ").map{Int($0)!}
let b:[Int] = readLine()!.split(separator: " ").map{Int($0)!}
let c:[Int] = readLine()!.split(separator: " ").map{Int($0)!}

var heights:[Int] = [a[0], b[0], c[0]]
heights.sort{$1 < $0}

let dictionary:[Int:String] = [a[0]:"A", b[0]:"B", c[0]:"C"]
for height in heights {
    print(dictionary[height]!)
}