function main()
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = ['!','@','#','$','%','^','&','*','(',')','-','+']
    c1 = 1
    c2 = 1
    c3 = 1
    c4 = 1
    n = parse(Int64,readline())
    s = readline()
    for i in s
        if(c1 == 1)
            for j in numbers
                if i==j
                    c1 -= 1
                    break
                end
            end
        end
        if(c2 == 1)
            for j in lower_case
                if i==j
                    c2 -= 1
                    break
                end
            end
        end
        if(c3 == 1)
            for j in upper_case
                if i==j
                    c3 -= 1
                    break
                end
            end
        end
        if(c4 == 1)
            for j in special_characters
                if i==j
                    c4 -= 1
                    break
                end
            end
        end
        if( c1+c2+c3+c4 == 0)
            break
        end
    end
    if(n<6)
        a = 6-n
        if(c1+c2+c3+c4<a)
            println(a)
        else
            println(c1+c2+c3+c4)
        end
    else
        println(c1+c2+c3+c4)
    end
end

main()