#include <iostream>
#include <cmath>
#include <algorithm>

int solution(int M, int N) {
    int total_area = 4 * N + M;

    int x = static_cast<int>(:sqrt(total_area));

    while (x > 0) {
        int needed_tiles = x * x;

        int max_2x2_tiles = (x / 2) * (x / 2);

        if (needed_tiles <= 4 * min(N, max_2x2_tiles) + M) {
            return x;
        }

        --x;
    }

    return 0;
}

def foodItems(i1, i2, i3, i4):
    a = sorted(i4)
    if a[-1] - a[0] > i1 - 1:
        return -1
    m, c = 1, a[0]
    for x in a[1:]:
        if x - c > i1 - 1:
            m += 1
            c = x
    return m