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 ////////////////////

const nums = "0123456789"
const lc = "abcdefghijklmnopqrstuvwxyz"
const uc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
const sc = "!@#$%^&*()-+"
const min_length = 6

function hasThing(str, thing) {
    return thing.split("").reduce((a, c) => a || (str.includes(c)), false);
}

function boolToNum(bool) {
    return bool ? 0 : 1;
}

function minimumNumber(n, password) {
    // Return the minimum number of characters to make the password strong
    const minCheck = n < min_length ? min_length - n : 0;
    const charsNeeded = [nums, lc, uc, sc].reduce((a, c) => a + boolToNum(hasThing(password, c)), 0);
    return Math.max(minCheck, charsNeeded);
}

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

}