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

#define MUNITNUM 65535
#define LIMIT_N 15000
#define DIGIT_UNIT 4

#define DTYPE long

static char *z[] = {
  "",
  "0",
  "00",
  "000",
};
  
int
main(int argc, char **argv)
{
  int i, j;
  DTYPE n, N;
  DTYPE s[MUNITNUM];
  DTYPE mufactor, zeros;
  DTYPE mmax = 0, carry = 0, mmul = 0, mmax_s;

  if (argc != 2) {
    fprintf(stderr, "usage: %s N\n", argv[0]);
    exit(1);
  }

  N = atoi(argv[1]);

  if (N > LIMIT_N) {
    fprintf(stderr, "error: N too large (max allowed is %d)\n", LIMIT_N);
    exit(1);
  }

  s[0] = 1;
  mufactor = (int)pow((double)10, (double)DIGIT_UNIT);

  for (i = 2; i <= N; i++) {
    mmax_s = mmax;
    for (j = 0; j <= mmax_s; j++) {
      n = s[j];
      mmul = n * i + carry;
      carry = mmul / mufactor;
      mmul %= mufactor;
      s[j] = mmul;
      if ((carry != 0) && (j == mmax)) {
        mmax++;
        s[mmax] = carry;
        carry = 0;
      }
    }
  }
  for (i = mmax; i >= 0; i--,zeros=0) {
    if (i != mmax) {
      ((s[i] < 10) && (zeros = 3)) ||
      ((s[i] < 100) && (zeros = 2)) ||
      ((s[i] < 1000) && (zeros = 1));
      printf ("%s", z[zeros]);
    }
    printf ("%d", s[i]);
  }

  printf ("\n");
  exit(0);
}