{
    stack<int> a1;
    stack<int> b1;
    int val = 0;
    int tmp = 0;
    int t = 0;
    for (int i = a.size() - 1; i >= 0; i--)
    {
        a1.push(a[i]);
    }
    for (int i = b.size() - 1; i >= 0; i--)
    {
        b1.push(b[i]);
    }

    while (tmp <= maxSum && (!a1.empty() || !b1.empty()))
    {
        val = t;

        if (!a1.empty() && (b1.empty() || a1.top() <= b1.top()))
        {
            tmp += a1.top();
            a1.pop();
            t += 1;
        }
        else if (!b1.empty())
        {
            tmp += b1.top();
            b1.pop();
            t += 1;
        }
    }
    return val;
}