Untitled

import java.util.*;

public class Main {
    static class Lender {
        int lend;
        int payback;

        public Lender(int lend, int payback) {
            this.lend = lend;
            this.payback = payback;
        }
    }
    
    public static int countMaxDays(List<Integer> lend, List<Integer> payback) {
        int n = lend.size();
        Lender[] lenders = new Lender[n];
        for (int i = 0; i < n; i++) {
            lenders[i] = new Lender(lend.get(i), payback.get(i));
        }
        Arrays.sort(lenders, Comparator.comparingInt(l -> l.lend));
        int days = 0;
        int prevPayback = 0;
        for (Lender lender : lenders) {
            if (lender.lend >= prevPayback) {
                days++;
                prevPayback = lender.payback;
            }
        }
        return days;
    }

    public static void main(String[] args) {
        List<Integer> lend = List.of(2, 1, 5);
        List<Integer> payback = List.of(2, 2, 5);
        List<Integer> lend1 = List.of(1, 1, 1, 2);
        List<Integer> payback1 = List.of(2, 2, 2, 3);
        System.out.println(countMaxDays(lend, payback)); // 3
        System.out.println(countMaxDays(lend1, payback1)); // 2
        
    }
}