package main

import (
    "fmt"
    "math"
)

func main() {
    var n float64
    fmt.Scan(&n)
    /*for i:=1;i<=n;i+=1{
        if (i*i)>n{
            fmt.Println(i-1)
            return
        }
        if (i*i)==n{
            fmt.Println(i)
            return
        }
    }*/
    fmt.Printf("%d", int(math.Sqrt(n)))
}