#include<iostream>
using namespace std;
int main()
{
	int n,i,x,p,d,nc,nt=0;
	cout<<"n="; cin>>n;
	for(i=1;i<=n;i++)
	{
		cout<<"x="; cin>>x;
		p=1;
		if(x==0 || x==1) p=0;
		else for(d=2;d<=x/2;d++)
			     if(x%d==0) p=0;
		if(p==1)
		{
			nc=0;
			while(x>0)
			{
				nc++;
				x=x/10;
			}
			nt=nt+nc;
		}
	}
	cout<<nt;
	return 0;
}