process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function minimumNumber(n, password) {
    // Return the minimum number of characters to make the password strong
    var numbers = "0123456789".split('')
    var lower_case = "abcdefghijklmnopqrstuvwxyz".split('')
    var upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('')
    var special_characters = "!@#$%^&*()-+".split('')
    var count = 0;
    var find = {
        n: false, 
        l: false,
        u: false,
        s: false
    }
    for(var i = 0; i < n; i ++) {
        var c = password.charAt(i);
        if(!find.n && findChar(numbers, c)) {
            count ++;
            find.n = true;
        }
        if(!find.l && findChar(lower_case, c)) {
            count ++;
            find.l = true;
        }
        if(!find.u && findChar(upper_case, c)) {
            count ++;
            find.u = true;
        }
        if(!find.s && findChar(special_characters, c)) {
            count ++;
            find.s = true;
        }
    }
    
    count = 4 - count;
    
    if(n + count < 6) {
        count = 6 - n;
    }
    
    function findChar(arr, c) {
        var l = arr.length;
        for(var i = 0; i < l; i ++) {
            if(c == arr[i]) return true;
        }
        return false;
    }
    
    return count;
}

function main() {
    var n = parseInt(readLine());
    var password = readLine();
    var answer = minimumNumber(n, password);
    process.stdout.write("" + answer + "\n");

}