백준 1931 c++

#include <iostream>
#include <vector>
#include <algorithm>
#include <limits.h>

using namespace std;

int input(int lower, int upper)
{
	//cout << "input()" << endl;
	int A;

	while (1)
	{
		cin >> A;
		if (A >= lower && A <= upper)
		{
			break;
		}
		else
		{
			;
		}
	}

	return A;
}

//void input_arr(int** A, int N)
void input_arr(vector <pair<int, int>> &A, int N)
{
	//cout << "input_arr()\n";
	int i;
	int temp1, temp2;

	for (i = 0; i < N; i++)
	{
		//A[i][0] = input(0, 2147483647);
		//A[i][1] = input(0, 2147483647);
		temp1 = input(0, INT_MAX);//begin
		temp2 = input(0, INT_MAX);//end
		A.push_back(make_pair(temp2, temp1));
	}

	return;
}

int find_result(vector <pair<int, int>> A, int N)
{
	//cout << "find_result()\n";
	int i, count = 1;
	int temp;

	/*for (i = 0; i < N; i++)
	{
		cout << A[i].first << " " << A[i].second << "\n";
	}*/

	temp = A[0].first;
	for (i = 1; i < N; i++)
	{
		if (temp <= A[i].second)
		{
			temp = A[i].first;
			count++;
		}
		else
		{
			;
		}
	}

	return count;
}

int main(void)
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int N;  /*, i;*/
	//int **timeTable;
	vector <pair<int, int>> timeTable;

	N = input(1, 100000);
	/*timeTable = new int* [N];
	for (i = 0; i < N; i++)
	{
		timeTable[i] = new int[2];
	}*/
	input_arr(timeTable, N);
	sort(timeTable.begin(), timeTable.end()
		/*,
		[](const std::pair<int, int>& a, const std::pair<int, int>& b) 
		{
		return a.second < b.second;
		}*/
	);//second 기준 오름차순 정렬
	cout << find_result(timeTable, N) << "\n";
	/*for (i = 0; i < N; i++)
	{
		delete[] timeTable[i];
	}
	delete[] timeTable;*/

	return 0;
}