// 解きかけ

open System

let n64 = stdin.ReadLine () |> int64
let n = n64 |> float

let mutable ans = Int32.MaxValue
let logn = log n

for i in 2..int (10. ** 3.) do
    let index = logn / log (float i) |> int
    let a = (n64 - int64((float i) ** (float index)) |> int) + i + index
    if a < ans then
        ans <- a
        
printfn "%d" ans