#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n, len1 = 6, len2 = 1, len3 = 1, len4 = 1, len5 = 1;
    string s;
    cin>>n>>s;
    
    for (int i = 0; i < s.size(); i++)
    {
        len1--;
        if ('A' <= s[i] and s[i] <= 'Z')
            len2--;
        else if ('a' <= s[i] and s[i] <= 'z')
            len3--;
        else if ('0' <= s[i] and s[i] <= '9')
            len4--;
        else
            len5--;
    }
    int ans = 0;
    
    while (len1 > 0)
    {
        if (len2 > 0)
            len2--;
        else if (len3 > 0)
            len3--;
        else if (len4 > 0)
            len4--;
        else if (len5 > 0)
            len5--;
        ans++;
        len1--;
    }
    ans += max(len2, 0)+max(len3, 0)+max(len4, 0)+max(len5, 0);
    cout<<ans<<"\n";
}