void insert(Node* &t, Node* &p) {
    if (t == nullptr) {
        t = p;
        return;
    }
    if (p->prior > t->prior) {
        swap(t, p);
        nodepair q = split(p, t->key);
        t->l = q.fi;
        t->r = q.se;
        upd(t);
        return;
    }
    if (p->key <= t->key) {
        t->val++; t->sum += p->key;
        insert(t->l, p);
    } else {
        t->val++; t->sum += p->key;
        insert(t->r, p);
    }
}

void remove(Node* &t, int x) {
    if (t->key == x) {
        t = merge(t->l, t->r);
        if (t) upd(t);
        return;
    }
    if (x < t->key) {
        t->val--; t->sum -= x;
        remove(t->l, x);
    } else {
        t->val--; t->sum -= x;
        remove(t->r, x);
    }
}