#include <stdio.h>
	int main() 
	{
		int n,num=0;
		scanf("%d",&n);
     	int count1,count2=0;
			for(int i=0;i<n;i++)
			{   scanf("%d",&num);
		
				if(num<=60)
				{
					count1++;
				}
				else
					count2++;
			}
		double sum=count1*0.1+count2*0.2;
		printf("%.1f",sum);
		
	
	return 0;
			}