[Timus Online Judge] 1083. Factorials!!!

Try first time and got AC.
The point is how to get string.
Count how many '!' do user input.

Time Limit: 1.0 second Memory Limit: 16 MB Definition 1. n!!…! = n(n−k)(n−2k)…(n mod k), if k doesn’t divide n; n!!…! = n(n−k)(n−2k)…k, if k divides n (There are k marks ! in the both cases). Definition 2. X mod Y — a remainder after division of X by Y. For example, 10 mod 3 = 1; 3! = 3·2·1; 10!!! = 10·7·4·1. Given numbers n and k we have calculated a value of the expression in the first definition. Can you do it as well? Input contains the only line: one integer n, 1 ≤ n ≤ 10, then exactly one space, then k exclamation marks, 1 ≤ k ≤ 20. Output contains one number — n!!…! (there are k marks ! here).

#include
#include


int Factorials(int n,int k){

       if (n<=k){
           if(n%k == 0)
               return k;
           else
               return n%k;
               
       }
       else
          return n*Factorials(n-k,k); 

}

int main(void){

      size_t nbytes = 2;
      int n_num,k_num;
      char *line; 
      line = (char *) malloc (nbytes+1);

      scanf("%d ",&n_num);

      k_num = 0;
      while ( fgets(line, nbytes , stdin) != NULL ){
             k_num++; 
      }      
      k_num--;
      
      printf("%d",Factorials(n_num,k_num));

return 0;
}