int pickingNumbers(vector<int> a) {
    sort(a.begin(), a.end());
    int c = 0;
    int i = a[0];
    int l = 0;
    for (auto n : a) {
        if (n - i > 1) {
            l = max(c, l);
            c = 1;
            i = n;
        } else {
            c++;
        }
    }
    return max(l, c);
}