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
    let as =password
let numbers = "0123456789"
let lower_case = "abcdefghijklmnopqrstuvwxyz"
let upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
let special_characters = "!@#$%^&*()-+"
let required={
    chars:1,
    numbers:1,
    lower_case:1,
    upper_case:1
}
for(let a of as){
    if(special_characters.includes(a)){
        if(required.chars>0)
        required.chars-=1
        continue
    }
    if(numbers.includes(a)){
        if(required.numbers>0)
        required.numbers-=1
        continue
    }
    if(lower_case.includes(a)){
        if(required.lower_case>0)
        required.lower_case-=1
        continue
    }
    if(upper_case.includes(a)){
        if(required.upper_case>0)
        required.upper_case-=1
        continue
    }

}
let c = 0
for(let req in required){
    c+=required[req]
}
return(Math.max(6-as.length,c))
}

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

}