struct node{
    node *l, *r;
    int v = 0;
    node(): l(nullptr), r(nullptr) {}
    node(node *l, node *r): l(l), r(r) {pull();}
    void pull() {if(l) v = max(l->v, r->v);}
};

node *build(int l,int r) {
    int mid = l+r >> 1;
    if(l+1 == r) return new node;
    return new node(build(l, mid), build(mid, r));
}

void add(node *a, int l, int r, int pos, int v) {
    int mid = l+r >> 1;
    if(l+1 == r) a->v += v;
    else if(m <= pos) add(a->r, m, r, pos, v);
    else add(a->l, l, m, pos, v);
    a->pull();
}