var dic = [Int:Int64]() let goal = Int(readLine()!)! func getAns(idx:Int) -> Int64 { if goal - idx == 1 { return 1 } if goal - idx == 2 { return 2 } if let dp = dic[idx] { return dp } let ans = getAns(idx: idx+2) + getAns(idx: idx+1) dic[idx] = ans return ans } let ans = getAns(idx: 0) print(ans)