int toys(vector<int> w) {
    sort(w.begin(),w.end());
    int c=0;
    size_t i = 0;
    while (i < w.size()) {
        int max = w[i] + 4;
        while (i < w.size() && w[i] <= max) {
            i++;
        }
        c++;
    }
    
    return c;
}