I have read all comments below, but my program still gets WA...

#include <stdio.h>
#include <math.h>

int main () {
 int hh, dd, mm, danger, n;
 double x1, x2, x3, y1, y2, y3, a1, a2, a3, b1, b2, b3;
 char ns1, ns2, we1, we2;
 double x, y, z, a, b, c, res, Phi, Psi;
 char s1[3], s2[3], s3[3];
 const double R = 6875;
 const double Pi = 3.1415926;
 char s [100];
 int q = 1;
 while (q) {
  if (scanf ("Message #%d.\n", &n) == EOF) break;
  scanf ("Received at %2d:%2d:%2d.\n", &hh, &dd, &mm);
  scanf ("%[^\n]\n", s);
  scanf ("%2lf^%2lf'%2lf%c ", &x1, &x2, &x3, &c);
  scanf ("%cL\n", &ns1);
  scanf ("and %2lf^%2lf'%2lf%c ", &y1, &y2, &y3, &c);
  scanf ("%cL.\n", &we1);
  scanf ("%[^\n]\n", s);
  scanf ("%2lf^%2lf'%2lf%c ", &a1, &a2, &a3, &c);
  scanf ("%cL\n", &ns2);
  scanf ("and %2lf^%2lf'%2lf%c ", &b1, &b2, &b3, &c);
  scanf ("%cL.\n", &we2);
  scanf ("%[=]", s);
  if (scanf ("\n") == EOF) q = 0;
  Phi = Pi / 180 * (x1 + x2 / 60 + x3 / 3600);
  if (ns1 == 'S') Phi *= -1;
  Psi = Pi / 180 * (y1 + y2 / 60 + y3 / 3600);
  if (we1 == 'E') Psi *= -1;
  x = cos (Phi) * cos (Psi);
  y = cos (Phi) * sin (Psi);
  z = sin (Phi);
  Phi = Pi / 180 * (a1 + a2 / 60 + a3 / 3600);
  if (ns2 == 'S') Phi *= -1;
  Psi = Pi / 180 * (b1 + b2 / 60 + b3 / 3600);
  if (we2 == 'E') Psi *= -1;
  a = cos (Phi) * cos (Psi);
  b = cos (Phi) * sin (Psi);
  c = sin (Phi);
  res = R * acos (a*x + b*y + c*z) / 2;
  danger = (res < 99.995);
  if (res < 0.005) res = 0;
  printf ("The distance to the iceberg: %.2lf miles.\n", res);
  if (danger)
   printf ("DANGER!\n");
 };
 return 0;
}