void update(int v,int left,int right,int pos,int new_val) {
	if (left + 1 == right) {
		tree[v] = { new_val,new_val };
		return;
	}
	int mid = (left + right) / 2;
	if (pos < mid)
		update(2 * v, left, mid, pos, new_val);
	else
		update(2 * v + 1, mid, right, pos, new_val);
	tree[v] = { max(tree[2 * v].first,tree[2 * v + 1].first) , min(tree[2 * v].second,tree[2 * v + 1].second) };
}