#include<iostream>
#include<set>
#include<vector>
#include<math.h>
#include<stdio.h>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
//#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<long long,long long> pll;
typedef vector<int> vi;
typedef vector<long long> vll;
#define pb push_back
template<typename T>void read(T &x)
    {
        register T c = getchar(); x = 0; int t = 0;
        if (c == '-') t = 1, c = getchar();
        for (; (c < 48 || c > 57); c = getchar());
        for (; c > 47 && c < 58; c = getchar()) {
            x = (x << 1) + (x << 3) + c - 48;
        }
        if (t) x = -x;
    }
int main()
{
//ios_base::sync_with_stdio(false); cin.tie(NULL);
int n;
cin>>n;
string s;
cin>>s;
bool arr[4]={0};
int count=0;
for(int i=0;i<s.length();i++)
{
    if(s[i]>='0' && s[i]<='9')arr[0]=1;
    else if(s[i]>='a' && s[i]<='z')arr[1]=1;
    else if(s[i]>='A' && s[i]<='Z')arr[2]=1;
    else arr[3]=1;
}
for(int i=0;i<4;i++)if(arr[i])count++;

if(s.length()>=6)cout<<4-count;
else
{
    if((n+(4-count))>=6)cout<<4-count;
    else
    {
        int n=s.length();
        n+=(4-count);
        cout<<(4-count)+6-n;
    }
}
}