Bus

#include <iostream>

using namespace std;

int main() {
    int passengers, stations, outputPassengers, inputPassengers;
    cin >> passengers, stations;

    for (int i = 1; i <= stations; i++) {
        cin >> outputPassengers >> inputPassengers;

        passengers += inputPassengers - outputPassengers;

        if (i % 2 == 1) {
            passengers += 2;
        }
        else {
            passengers -= 2;
        }
    }

    cout << "The final number of passengers is : " << passengers << endl;
    return 0;
}