#include <iostream>
#include <cstdio>
#include <cmath>

using namespace std;

int main()
{
    long long x;

    cin>>x;

    long long l=x,r=x*2,mid;

    while (l<r)
    {
        mid=(l+r)/2;
        if (log(mid*1.0)*mid-mid+0.5*log(mid)+0.999999<x*log(x))
        {
            l=mid+1;
        }
        else
        {
            r=mid;
        }
    }

    cout<<l;

    return 0;
}

题解在这