let firstArray = readLine()!.characters.split(" ").map{Int(String($0))!}
let secondArray = readLine()!.characters.split(" ").map{Int(String($0))!}
let thirdArray = readLine()!.characters.split(" ").map{Int(String($0))!}



var twoDArray = [Int]()
twoDArray = firstArray
twoDArray += secondArray
twoDArray += thirdArray

let duplicate = Array(Set(twoDArray.filter({ (i: Int) in twoDArray.filter({ $0 == i }).count > 1})))
var missingIndex = 0

let indexofelement = twoDArray.indexOf(5)
for value in 1...9
{
    let index = twoDArray.indexOf(value)
    if index == nil
    {
       missingIndex = value
       break
    }
}
let cost = duplicate[0] - missingIndex
print(abs(cost))