def minimumNumber(n, password):
    count = 0    
    if any(i.isdigit() for i in password)==False:
        count+=1
    if any(i.islower() for i in password)==False:
        count+=1
    if any(i.isupper() for i in password)==False:
        count+=1
    if any(i in '!@#$%^&*()-+' for i in password)==False:
        count+=1
    return max(count,6-n)

int CharFamily(char c) 
{
   if(c >= '0' && c <= '9') return 0;
   if(c >= 'a' && c <= 'z') return 1;
   if(c >= 'A' && c <= 'Z') return 2;
   return 3;
}

int main() 
{
    int n; cin >> n;
    char c;
    bitset<4> mask;

    while (cin >> c)
    {
        mask.set(CharFamily(c));
    }
    cout << max(6-n, 4-(int)mask.count());
}

private static int checkPass(String s) {
		int count = 0;
		
		Pattern patternDigit = Pattern.compile("(\\d)");
		Pattern patternUpper = Pattern.compile("([A-Z])");
		Pattern patternLower = Pattern.compile("([a-z])");
		Pattern patternSpecial = Pattern.compile("(\\W)");
        
		Matcher matcherDigit = patternDigit.matcher(s);
		Matcher matcherUpper = patternUpper.matcher(s);
		Matcher matcherLower = patternLower.matcher(s);
		Matcher matcherSpecial = patternSpecial.matcher(s);
		
		if (!matcherDigit.find()) {
			count++;
		}
		if (!matcherUpper.find()) {
			count++;
		}
		if (!matcherLower.find()) {
			count++;
		}
		if (!matcherSpecial.find()) {
			count++;
		}
		if ((count+s.length())<6) {
			count = count + 6-(count+s.length());
		}
		return count;
	}

static int minimumNumber(int n, String password) {
        
        int lc=0,uc=0,no=0,sc=0;
        int sum=0;
        
        String lowercase = ".*[a-z]+.*";
        String uppercase = ".*[A-Z]+.*";
        String num = ".*[0-9]+.*";
        String specialchar = ".*[-!@#$%^&*()+]+.*"; 
        //Regex for pattern matching
        
        if(!(password.matches(lowercase)))
            lc++; 
        //if there is no match to a lowercase,"lc" is increased by 1.
    
        if(!(password.matches(uppercase)))
            uc++; 
        //if there is no match to an uppercase,"uc" is increased by 1.
    
        if(!(password.matches(num)))
            no++; 
        //if there is no match to a number,"no" is increased by 1.
    
        if(!(password.matches(specialchar)))
            sc++; 
        //if there is no match to a specialCharacter,"sc" is increased by 1.
        
        
        sum=lc+uc+sc+no;
        
        return (sum>(6-n))?sum:(6-n);
    }

function minNumber(n, pass) {
    const c = [/[0-9]/, /[a-z]/, /[A-Z]/, /[!@#$%^&*()\-+"]/]
            .map(r => !r.test(pass))
            .filter(Boolean).length
    
    return Math.max(c,6-n);
}

    static int minimumNumber(int n, String password) {       
        int up_count=0,low_count=0,sp_count=0,num_count=0,tba=0;
        for(int i=0;i<n;i++)
        {
           if(Character.isDigit(password.charAt(i)))
                num_count++;
             if(Character.isUpperCase(password.charAt(i)))
               up_count++;
             if(Character.isLowerCase(password.charAt(i)))
               low_count++;
            if(password.charAt(i)!= 32 &&(password.charAt(i) < 48 || password.charAt(i) > 57) && 	
		(password.charAt(i) < 65 || password.charAt(i) > 90) && 	
		(password.charAt(i) < 97 || password.charAt(i)> 122))
                sp_count++;	
        }
        
            if(num_count==0)
                tba++;
               if(up_count==0)
               tba++;
               if(low_count==0)
               tba++;
                if(sp_count==0)
               tba++;
        
        if(n+tba<6)
        {
            while(n+tba<6)
                tba++;
        }
        return tba;
    }

num=int(input())
st=input()
n=0
l=0
u=0
s=0
count=0
spec="!@#$%^&*()-+"
for c in st:
    if c.isupper():
        u=u+1
    elif c.islower():
        l=l+1
    elif c.isdigit():
        n=n+1
    elif c in spec:
        s=s+1
if ( u==0 ):
    count=count+1
if ( l==0 ):
    count=count+1
if ( n==0 ):
    count=count+1
if ( s==0 ):
    count=count+1
if( (u+l+s+n+count) < 6 ):
    count=count+(6-(u+l+s+n+count))
print(count)