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

int main (int argc, char *argv[]) {
  int max; sscanf (argv[1], "%d", &max);
  int tasks; sscanf (argv[2], "%d", &tasks);
  if (max % tasks != 0) return 1;
  int sum = 0;
  #pragma omp parallel
    {
      #pragma omp single
        for (int t = 0; t < tasks; t++) {
          #pragma omp task
            {
              sleep (1);
              int local_sum = 0;
              int lo = (max / tasks) * (t + 0) + 1;
              int hi = (max / tasks) * (t + 1) + 0;
              printf ("%d: %d..%d\n", omp_get_thread_num(), lo, hi);
              for (int i = lo; i <= hi; i++)
                local_sum = local_sum + i;
              #pragma omp atomic
                sum = sum + local_sum;
            }
        }
    }
  printf ("%d\n", sum);
  return 0;
}