#include <iostream>
#include <vector>

using namespace std;


unsigned long long binpow (unsigned long long a, unsigned long long n) {
    if (n <= 0)
        return 1;
    if (n % 2 == 1)
        return binpow (a, n-1) * a;
    else {
        unsigned long long b = binpow (a, n/2);
        return b * b;
    }
}


int check(unsigned long long m, unsigned long long k)
{
    if( k == 1) return 1;
    int flag;
    unsigned long long t,x,tr;
    for( t = 1;t<m/2;t++)
    {
        for(x =2;x<m/2;x++)
        {
             tr = t*(x)*binpow(x+1,k-2);
            if(tr > m)
            {
                if(x == 2)
                {
                    flag == 0;
                }
                break;
            }
            if(tr == m)
            {
                return 1;
            }
            if(flag == 1)
            {
                return 0;
            }
        }
    }
    return 0;
}

int main()
{
    unsigned long long m;
    cin  >> m;
    int flag;
    unsigned long long left = 0;
    unsigned long long right = m;
    unsigned long long mid;
    while(left+1<right)
    {
        mid = (left + right)/2;
        if(check(m,mid) == 1)
        {
            left = mid;
            flag = 1;
        }
        else{
            right = mid;
            flag = 0;
        }
    }
    if(flag == 1)
    {
        cout << mid;
    }
    else{
        cout << mid -1;
    }
    return 0;
}