#include <iostream>
#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <unordered_map>
#include <string>

using namespace std;


int main()
{
    int t,a,ctr,b,m,n,i,j,len,pa,f,flag,sum = 0;
	string str;
	/*while(t--)
	{*/
        flag = 0;
        cin >>n>>str;
        int l = 0, u = 0,d = 0, s = 0;



        for(i = 0;i<n;i++)
        {
            if(str[i] >= 97 && str[i] <= 122)
                l = 1;
            else if(str[i] >= 65 && str[i] <= 90)
                u = 1;
            else if(str[i] >= 48 && str[i] <= 57)
                d = 1;
            else
                s = 1;
        }

        if(l == 0) sum++;
        if(u == 0) sum++;
        if(s == 0) sum++;
        if(d == 0) sum++;

        if(n<6)
        {
            if(sum > 6-n-1)
                cout<<sum;
            else
                cout<<6-n;

        }
        else if(n>=6)
        {
            cout<<sum;
        }



 //   }

    return 0;
}