#include<stdio.h>
#include<stdlib.h>
int main(void)
{
    FILE *fisierin;
       int  fact = 1, nr = 0, i = 2, u, rez, p ;
    if((fisierin = fopen("fisier.in", "w+b"))== NULL)
{
    puts("Fisierul nu poate fi deschis.");
        exit(1);
    }
          scanf("%d", &p);
          fwrite(&p, sizeof(int), 1, fisierin);
           fclose(fisierin);
                if ( p == 0)printf("n = 1");
                else
    {
        while(nr < p )
            {
                fact  = fact * i;
                i ++;
                u = fact % 10;
                while(u == 0)
                {
                    nr ++;
                    fact =  fact / 10;
                    u = fact % 10;
                }
            }
            rez = i -1;

        }

    FILE * fisierout;
    if((fisierout = fopen("fisier.out", "wb"))== NULL)
{
    puts("Fisierul nu poate fi deschis.");
        exit(1);
    }
   fwrite(&rez, sizeof(int), 1, fisierout);
    fclose(fisierout);
    return 0;

}