#include <stdio.h>
#include <omp.h>

int main()
{
    int a = 70;

#pragma omp parallel shared(a) num_threads(8)
    {
        printf("number = %i\n", omp_get_thread_num());

#pragma omp critical
        {
            --a;
        }
    }

    printf("a = %i", a);
}