#include <bits/stdc++.h>
using namespace std;
bool check(long long int actnum)
{
int num[10]={2,3,5,7,11,13,17,19,23,29};
int c=0,p;
if(actnum==0 || actnum==1)
{
return false;
}
if(std::find(std::begin(num),std::end(num), actnum) != std::end(num))
{
return true;
}
// reverse(b1.begin(), b1.end());
for (p = 0; p<10; p++)
{
if(actnum%num[p]==0)
{
return false;
} }
if(p==10)
{
return true;}
else
{
return false;}}
using namespace std;
int main()
{
int n,p;
char a[1000];
cin>>n;
cin.ignore();
string s="";
cin.get(a,1000);
int num[10]={2,3,5,7,11,13,17,19,23,29};
int c=0;
for (int i = 0; a[i]!='\0'; i++)
{
for (int j = i; a[j]!='\0'; j++)
{
string b="";
for (int k = i; k<=j; k++)
{
b=b+a[k];
}
long long int actnum=stoi(b),flag=0;
if(check(actnum))
{
if(s.find(b)>10000)
{
s=s+b;
c++;
}}}}
cout<<c;
return 0;
}