#include<stdio.h>

int main()
{
FILE *f=fopen("fact.in", "r");
FILE *g=fopen("fact.out", "w");


long k=1, p, n=5;

fscanf(f, "%ld", &p);

while(k<=p)
	{
	n+=5;
	k++;
	}

fprintf(g, "%ld", n);


fclose(f);
fclose(g);
return 0;
}