#include <bits/stdc++.h>

using namespace std;

const int maxn = , INF = 0x7fffffff;

typedef long long LL;

LL n, k;

int main()

{

    scanf("%lld", &n);

    if(n <= )

    {

        cout<<  <<endl;

        return ;

    }

    LL tmp = n;

    LL l = , r = n;

    while(l <= r)

    {

        LL sum = ;

        tmp = n;

        LL mid = l + (r - l) / ;

        while(tmp > )

        {

            LL t = min(mid, tmp);

            tmp -= t;

            tmp -= tmp / ;

            sum += t;

        }

        if(sum >= (n+) / ) r = mid - ;

        else l = mid + ;

    }

    cout<< l <<endl;

    return ;

}