This is my source code:

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

double w1,l1;
double w2,l2;

double x1,x2,x3;
double Y1,Y2,Y3;

const double r = 3437.5;
const double pi = 3.14159265358979323846;

int scan(void)
{
    int num, hh, mm, ss;
    double x1,x2,x3;
    char str[5];

    if(scanf("Message #%d.\n", &num) <= 0)
        return 0;
    scanf("Received at %d:%d:%d.\n", &hh, &mm, &ss);
    scanf("Current ship&#8217;s coordinates are\n");

    scanf("%lf^%lf'%lf\" %s\n", &x1, &x2, &x3, str);
    if( str[0] == 'S' )
    {
        x1=-x1;
        x2=-x2;
        x3=-x3;
    }

    w1 = (x1+x2/60+x3/3600)/180*pi;

    scanf("and %lf^%lf'%lf\" %s\n", &x1, &x2, &x3, str);
    if( str[0] == 'E' )
    {
        x1=-x1;
        x2=-x2;
        x3=-x3;
    }

    l1 = (x1+x2/60+x3/3600)/180*pi;

    scanf("An iceberg was noticed at\n");

    scanf("%lf^%lf'%lf\" %s\n", &x1, &x2, &x3, str);
    if( str[0] == 'S')
    {
        x1=-x1;
        x2=-x2;
        x3=-x3;
    }

    w2 = (x1+x2/60+x3/3600)/180*pi;

    scanf("and %lf^%lf'%lf\" %s\n", &x1, &x2, &x3, str);
    if( str[0] == 'E')
    {
        x1=-x1;
        x2=-x2;
        x3=-x3;
    }

    l2 = (x1+x2/60+x3/3600)/180*pi;

    scanf("===\n");
    return 1;
}

void coord(double w, double l, double& a1, double& a2, double& a3)
{
    a1 = cos(w)*cos(l);
    a2 = cos(w)*sin(l);
    a3 = sin(w);
}

double dist2(double a1, double a2, double a3, double b1, double b2,
double b3)
{
    return (a1-b1)*(a1-b1)+(a2-b2)*(a2-b2)+(a3-b3)*(a3-b3);
}

double doit(void)
{
    coord(w1,l1, x1, x2, x3);
    coord(w2,l2, Y1, Y2, Y3);


    double res = r * acos (x1*Y1 + x2*Y2 + x3*Y3);
    return res;
/*
      double x = dist2(x1,x2,x3,Y1,Y2,Y3);
    double cosfi = 1-x/2;
    double fi = acos(cosfi);

     return fi*r;
*/

}

int main(void)
{
#ifndef ONLINE_JUDGE
    freopen("1030.in", "r", stdin);
#endif


    while(scan())
    {
        double res = doit();

        if ((unsigned)printf("The distance to the iceberg: %
0.2lf miles.\n",res) <
            strlen("The distance to the iceberg: 100.00
miles.\n") )
            printf("DANGER!\n");
/*
        printf("The distance to the iceberg: %.2lf miles.\n",
res);
        if(res<99.995)
            printf("DANGER!\n");
*/
    }

#ifndef ONLINE_JUDGE
    fclose(stdin);
#endif
    return 0;
}