One tradition of ACM-ICPC contests is that a team gets a balloon for every solved problem. We assume that the submission time doesn't matter and teams are sorted only by the number of balloons they have. It means that one's place is equal to the number of teams with more balloons, increased by 1 . For example, if there are seven teams with more balloons, you get the eight place. Ties are allowed. You should know that it's important to eat before a contest. If the number of balloons of a team is greater than the weight of this team, the team starts to float in the air together with their workstation. They eventually touch the ceiling, what is strictly forbidden by the rules. The team is then disqualified and isn't considered in the standings. A contest has just finished. There are n teams, numbered 1 through n . The i -th team has t i balloons and weight w i . It's guaranteed that t i doesn't exceed w i so nobody floats initially. Limak is a member of the first team. He doesn't like cheating and he would never steal balloons from other teams. Instead, he can give his balloons away to other teams, possibly making them float. Limak can give away zero or more balloons of his team. Obviously, he can't give away more balloons than his team initially has. What is the best place Limak can get? The first line of the standard input contains one integer n ( 2 ≤ n ≤ 300 000 ) — the number of teams. The i -th of n following lines contains two integers t i and w i ( 0 ≤ t i ≤ w i ≤ 10 18 ) — respectively the number of balloons and the weight of the i -th team. Limak is a member of the first team. Print one integer denoting the best place Limak can get. In the first sample, Limak has 20 balloons initially. There are three teams with more balloons ( 32 , 40 and 45 balloons), so Limak has the fourth place initially. One optimal strategy is: Limak gives 6 balloons away to a team with 32 balloons and weight 37 , which is just enough to make them fly. Unfortunately, Limak has