import sys
def max_kill(dist, speed):
    # 计算每个敌人到达基地的最早整数分钟 time = ceil(dist/speed)
    times = [(d + s - 1) // s for d, s in zip(dist, speed)]
    times.sort()  # 贪心：按到达时间从早到晚处理
    # 第 k 分钟开始进行第 k 次消灭（k 从 0 开始）
    for k, t in enumerate(times):
        # 若 t <= k，表示敌人在第 k 分钟开始前/恰好开始时到达，来不及消灭
        if t <= k:
            return k
    return len(times)
def main():
    data = list(map(int, sys.stdin.read().strip().split()))
    n = data[0]
    dist = data[1:1 + n]
    speed = data[1 + n:1 + 2 * n]
    print(max_kill(dist, speed))

if __name__ == "__main__":
    main()

#include <bits/stdc++.h>
using namespace std;

// 题面功能：返回最多能消灭的敌人数
int maxKill(const vector<int>& dist, const vector<int>& speed) {
    int n = (int)dist.size();
    vector<int> times(n);

    // time = ceil(dist/speed) = (dist + speed - 1) / speed
    for (int i = 0; i < n; i++) {
        times[i] = (dist[i] + speed[i] - 1) / speed[i];
    }

    sort(times.begin(), times.end()); // 贪心：先处理最早到达的敌人

    for (int k = 0; k < n; k++) {
        // 第 k 分钟开始进行第 k 次消灭
        // 若 times[k] <= k，则敌人已到达/恰好到达导致失败
        if (times[k] <= k) return k;
    }
    return n;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;
    vector<int> dist(n), speed(n);
    for (int i = 0; i < n; i++) cin >> dist[i];
    for (int i = 0; i < n; i++) cin >> speed[i];

    cout << maxKill(dist, speed) << "\n";
    return 0;
}

import java.util.*;
public class Main {
    // 题面功能：返回最多能消灭的敌人数
    static int maxKill(int[] dist, int[] speed) {
        int n = dist.length;
        int[] times = new int[n];
        // 计算每个敌人到达基地的最早整数分钟：time = ceil(dist/speed)
        for (int i = 0; i < n; i++) {
            times[i] = (dist[i] + speed[i] - 1) / speed[i];
        }
        // 贪心：按到达时间从早到晚处理
        Arrays.sort(times);
        // 第 k 分钟开始进行第 k 次消灭（k 从 0 开始）
        for (int k = 0; k < n; k++) {
            // 若 times[k] <= k，表示敌人在你开枪前已到达/恰好到达，游戏结束
            if (times[k] <= k) return k;
        }
        return n;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] dist = new int[n];
        int[] speed = new int[n];
        // 输入 dist
        for (int i = 0; i < n; i++) dist[i] = sc.nextInt();
        // 输入 speed
        for (int i = 0; i < n; i++) speed[i] = sc.nextInt();
        System.out.println(maxKill(dist, speed));
    }
}