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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int n;
    cin>>n;
    char c[n];
    for(int i=0;i<n;i++)
        cin>>c[i];
    int count[4]={0};
    for(int i=0;i<n;i++)
    {
        if(c[i]>='0' && c[i]<='9')
           count[0]++;
        else if(c[i]>='a' && c[i]<='z')
           count[1]++;
        else if(c[i]>='A' && c[i]<='Z')
           count[2]++;
        else
            count[3]++;
        
     }
    int cnt=0;
    for(int i=0;i<4;i++)
    {
        if(count[i]==0)
            cnt++;
    }
    int no=n+cnt;
    if(no>6)
        cout<<cnt<<endl;
    else
        cout<<(6-n)<<endl;
    
    return 0;
}