1110번 '더하기 사이클'

let input = Int(readLine()!)!
 
var count = 0
var temp: Int = input
var tempToString = String(temp)
repeat{
    if(temp < 10){
        tempToString = "0"+tempToString
    }
    let sum = Int(tempToString[tempToString.startIndex].description)! + Int(tempToString[tempToString.index(tempToString.startIndex, offsetBy: 1)].description)!
    let sumToString = String(sum)
    let newNumber: Int
    if(sum < 10){
        newNumber = Int(tempToString[tempToString.index(tempToString.startIndex, offsetBy: 1)].description + sumToString[sumToString.index(sumToString.startIndex, offsetBy: 0)].description)!
    }
    else{
        newNumber = Int(tempToString[tempToString.index(tempToString.startIndex, offsetBy: 1)].description + sumToString[sumToString.index(sumToString.startIndex, offsetBy: 1)].description)!
    }
    temp = newNumber
    tempToString = String(newNumber)
    count += 1
} while(temp != input)
print(count)