#include<stdio.h>
int main()
{long unsigned i,k,p,a=100,r=1;
FILE *f=fopen("fact.in","r");
FILE *g=fopen("fact.out","w");
fscanf (f,"%ld",&p);
if (p==0) fprintf(g,"1");
else {i=0;k=0;
		while (k<p)
			{i=i+5;
			k++;}}
fprintf(g,"%ld",i-5);
fclose(f);
fclose(g);
return 0;}