import kotlin.coroutines.experimental.buildSequence

val D = "1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991"

inline fun add1(e: Int, c: Int): Int = e+c
inline fun add2(e: Pair<Int,Int>, c: Int): Int = e.first+e.second+c

fun f(s: String): Sequence<Int> {
    fun f(n: Int): Sequence<Int> =
        buildSequence {
            for (i in (D.length-1) downTo 0)
                yield(n * D.slice(i..i).toInt())
        }
    fun g(m: Int, n: Int): Sequence<Pair<Int,Int>> =
        buildSequence {
            yield(0); yieldAll(f(m)) //; yield(0)
        }.zip(buildSequence {
            yieldAll(f(n)); yield(0) //; yield(0)
        })
    tailrec fun <T> iter(c: Int, sq: Sequence<T>, add: (T, Int) -> Int): Sequence<Int> =
        buildSequence {
            val e = sq.firstOrNull()
            if (e!=null) {
                yield(add(e,c)%10); yieldAll(iter(add(e,c)/10, sq.drop(1), add))
            } else {
                if (c!=0) { yield(c) }
            }
        }
    return (
        if (s.length==1)
            iter(0, f(s.toInt()), ::add1)
        else
            iter(0, g(s.slice(0..0).toInt(),s.slice(1..1).toInt()), ::add2)
    )
}

fun fmt(s: String) =
    if (s.length!=D.length)
        s.slice(0..s.length-D.length-1)+"."+s.slice(s.length-D.length..s.length-1)
    else
        "0."+s

fun main(args: Array<String>) {
    val s = readLine()!!
    println(
        if (s=="100")
            D.slice(0..1)+"."+D.slice(2..D.length-1)
        else
            fmt(f(s).fold("", fun (a,e) = e.toString()+a))
    )
}