import java.util.Scanner;
public class Main {
public static boolean cbnum(long n) {
if(n==0||n==1){
return false;
}
for(int i=2;i<=n/2;i++){
if(n%i==0){
return false;
}
}
return true;
}
public static void main(String args[]) {
Scanner scn = new Scanner(System.in);
int n = scn.nextInt();
scn.nextLine();
String s = scn.nextLine();
int start = 0, end = 1, count = 0;
while (start < s.length()) {
while (end <= s.length()) {
long val = Long.parseLong(s.substring(start, end));
if (cbnum(val)) {
count++;
start = end-1;
break;
} else {
end++;
}
}
start++;
end = start + 1;
}
System.out.println(count);
}
}
0ut 0f 7 testcases 2 wernt wrong plz correct my code where i went wrong