#include <gmp.h>

int main()
{
   mpf_t fac;
   int i;

   mpf_init(fac);
   mpf_set_d(fac,(double) 1);

   for (i=1;i<40;i++) {
     mpf_mul_ui(fac, fac, (unsigned long) i);
   }

   gmp_printf("%.*Ff\n",40,fac);
}