#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    // Return the minimum number of characters to make the password strong
    unordered_map<char,int> umap;
    int scnt,dcnt,ucnt,lcnt;
    scnt=dcnt=ucnt=lcnt=1;
    umap['!']=1;umap['@']=1;umap['#']=1;umap['$']=1;umap['%']=1;umap['^']=1;
    umap['&']=1;umap['*']=1;umap['(']=1;umap[')']=1;umap['-']=1;umap['+']=1;
    for(int i=0;i<n;++i){
        if(p[i]>='0' && p[i]<='9' && dcnt ) dcnt--;
        else if(p[i]>='a' && p[i]<='z' && lcnt) lcnt--;
        else if(p[i]>='A' && p[i]<='Z' && ucnt) ucnt--;
        else if(umap.find(p[i])!=umap.end() && scnt) scnt--;
    }
    int sum=scnt+dcnt+ucnt+lcnt;
    if(n<6){
        if(sum>=6-n) return sum;
        else return 6-n;
    }
    else return sum;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}