Квадратная страна fast

#pragma once
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <vector>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <queue>
#include <stack>
#include <climits>
#include <deque>
#include <ctime>
#include <iomanip>
#include <bitset>
#include <unordered_map>
#include <unordered_set>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;

#define mh() make_heap()
#define poph() pop_heap()
#define pushh() push_heap()
#define sor(n) n.begin(), n.end()
#define rsor(n) n.rbegin(), n.rend()
#define mp make_pair
#define files freopen("input.txt", "rt", stdin); freopen("output.txt", "wt", stdout)
#define p(T) pair<T,T>
#define toch(x) cout.precision(x), cout.setf(ios::fixed)
#define znac(l) abs(l)/l
#define IOS ios::sync_with_stdio(false)
#define IOSB cin.tie(0), cout.tie(0);
const ll ok = ll(1e9 + 7);

bool chk2(ll n, ll k)
{
    for (ll i=1, j=k; i <= j; i++)
    {
        while (i*i + j*j > n)j--;
        if (i*i + j*j == n)return 1;
    }
    return 0;
}
bool chk4(ll n)
{
    ll p = 1;
    for (ll i = 0; i <= 50; i += 2)
    {
        if (n%p != 0)
            break;
        if (((n / p) - 7) % 8 == 0)
            return 1;
        p <<= 2;
    }
    return 0;
}
int main()
{
    IOSB;
    IOS;
#ifdef TheCompiler
    files;
#endif
    ll n, k;
    cin >> n;
    k = sqrt(n);
    if (k*k == n)
    {
        cout << 1 << endl;
        return 0;
    }
    if (chk2(n, k))
    {
        cout << 2 << endl;
        return 0;
    }
    if (chk4(n))
    {
        cout << 4 << endl;
        return 0;
    }
    cout << 3;

    return 0;
}