Bus

#include <stdio.h>

                                          // Bus
int main()
{
    int pass, stops;
    scanf("%d %d", &pass, &stops);
    int up, down;
    for (int i = 0; i < stops; i++)
    {
        scanf("%d %d", &down, &up);
        pass = pass - down + up;
    }
    pass = pass + stops % 2 * 2;
    printf("The final number of passengers is : %d\n", pass);
    return 0;
}