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, p) {
    if(n == 0) return 6;
    
    var numbers = "0123456789";
    var lower_case = "abcdefghijklmnopqrstuvwxyz";
    var upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    var special_characters = "!@#$%^&*()-+";
    
    var d = 0;
    if (!mcontains(p, numbers)) d++;
    if (!mcontains(p, lower_case)) d++;
    if(!mcontains(p, upper_case)) d++;
    if(!mcontains(p, special_characters)) d++;
    
    if (d + n < 6)  return 6-n;
    return d;
    
 }
 
 function mcontains(p,a){
     
     for(var i = 0; i < a.length; i++){
         if(p.indexOf(a[i]) != -1)
             {
                 return true;
             }
             
     }

     return false;
 }


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

}