module Program

open System

let solve a =
    let len = a |> Array.length
    let dp = Array.zeroCreate (len + 1)
    Array.iter (fun x -> dp.[x] <- dp.[x-1] + 1) a    
    let sortedNum = dp.[len]
    len - sortedNum

let N = Console.ReadLine() |> ignore
let a = 
    Console.ReadLine().Split()
    |> Array.map int

solve a
|> Console.WriteLine