#include <stdio.h>
#include <stdlib.h>

void main(int argc, char *argv[])
{
  double fdisp, fsample, fsource;

  if (argc < 3) {
    fprintf(stderr, "Usage: %s f_disp f_source\n", argv[0]);
    fprintf(stderr, "Program calculates f_sample = (f_disp + f_source)q / 17\n");
    exit(1);
  }

  fdisp   = atof(argv[1]);
  fsource = atof(argv[2]);

  fsample = (fdisp + fsource) / 17.0;
  printf("f_sample = %20.9f\n", fsample);
}