#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>

#define int long long

unsigned int f(int x)
{
    int i = sqrt(x);
    return x * i;
}

unsigned g(unsigned x)
{
    int a = x;
    int mod = (1LL << 32);

    while (1)
    {
        int l = 0, r = x + 2;

        while (r - l > 1)
        {
            int m = l + (r - l) / 2;

            if (f(m) <= x)
                l = m;
            else
                r = m;
        }

        if (f(l) == a)
            return l % mod;

        a += mod;
    }
}

int32_t main(void)
{
    unsigned x;
    scanf("%u", &x);

    printf("%u", g(x));

    return 0;
}