Wabbit Contest Badge Collection

You are a Wabbit with an initial level of $0$. You want to participate in contests to increase your strength and collect badges. There are $N$ contests in total. The $i$th contest is characterized by two integers $L_i$ and $X_i$. You can participate in contest $i$ if and only if your current level satisfies $\leq L_i$. When you participate, your level increases by $X_i$ and you earn one badge. You may attempt the contests in any order. Determine the maximum number of badges you can collect by choosing the optimal sequence of contests.

inputFormat

The first line contains a single integer $N$ ($1\le N\le 10^5$) representing the number of contests. Each of the following $N$ lines contains two space-separated integers $L_i$ and $X_i$, where $0\leq L_i, X_i\leq 10^9$.

outputFormat

Output a single integer — the maximum number of badges you can collect.

sample

2
1 100
10 1

2