题解 | 小红的优惠券

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
   
        int n = in.nextInt();
        int m = in.nextInt();

        int min=n;
        for (int i = 0; i < m; i++) {
            int money = in.nextInt();
            int less = in.nextInt();
            if (money<=n){
                min=Math.min(n-less,min);
            }
        }

        System.out.println(min);
    }
}