#include<iostream>

using namespace std;

int main()
{
    int n,a=0,b=0,c=0,d=0;
    cin >> n;
    char str[n];
    cin >> str;
    for(int i=0; i<n; i++)
    {
        if(str[i] >= 'a' && str[i] <= 'z')
        a=1;
        else if(str[i] >= 'A' && str[i] <= 'Z')
        b=1;
        else if(str[i] >= '0' && str[i] <= '9')
        c=1;
        else if(str[i] == '!' ||str[i]== '@' ||str[i]== '#' ||str[i]== '$' ||str[i]== '%' ||str[i]== '^' ||str[i]== '&' ||str[i]== '*' ||str[i]== '(' ||str[i]== ')' ||str[i]== '-' ||str[i]== '+')
        d=1;
    }
    if(n + 4 - (a + b + c + d) >= 6)
    cout << 4 - (a + b + c + d) << endl;
    else
    cout << 4 - (a + b + c + d) + 6 - (n + 4 - (a + b + c + d)) << endl;

}