#include<stdio.h>
int main()
{
	int m,n,s,c;
	scanf("%d%d",&m,&n);
	s=n/m;
	c=5*s;
	printf("%d",c);
	return 0;
}
/**************************************************************
	Problem: 1417
	User: admin
	Language: C
	Result: Accepted
	Time:16 ms
	Memory:1144 kb
****************************************************************/