#include<stdio.h>
int main()
{long P,x=0,i=5,y;
 FILE *f,*g;
 f=fopen("fact.in","r");
 g=fopen("fact.out","w");
 fscanf(f,"%ld",&P);
 while(x<P)
      {y=i;
       while(y%5==0)
		{y=y/5;
                 x++;}
       i+=5;}
 if(x==P) fprintf(g,"%ld",i-5);
 fclose(f);
 fclose(g);
 return 0;
}