dp=[]
n=gets.to_i
(n+1).times{
	dp<<Array.new(10,-1)
}
dp[0][0]=0
ans=0
xs=gets.split(" ").map{|e| e.to_i}
n.times{|i|
	x=xs[i]
	0.upto(9){|j|
		next if dp[i][j]==-1
		p1=(j+x)%10
		dp[i+1][p1]=[dp[i+1][p1],dp[i][j]+1].max
		dp[i+1][j]=[dp[i+1][j],dp[i][j]].max
		ans=[ans,dp[i+1][0]].max if p1==0
	}
}
puts ans