import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Pradyumn
 */
public class Solution {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastReader in = new FastReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        StrongPassword solver = new StrongPassword();
        solver.solve(1, in, out);
        out.close();
    }

    static class StrongPassword {
        public void solve(int testNumber, FastReader in, PrintWriter out) {
            int n = in.nextInt();
            char[] s = in.nextCharacterArray(n);
            int ct = 0;
            boolean f1 = false;
            boolean f2 = false;
            boolean f3 = false;
            boolean f4 = false;
            String ss = new String("!@#$%^&*()-+");
            for (int i = 0; i < n; ++i) {
                if (s[i] >= '0' && s[i] <= '9') f1 = true;
                if (s[i] >= 'a' && s[i] <= 'z') f2 = true;
                if (s[i] >= 'A' && s[i] <= 'Z') f3 = true;
                if (ss.indexOf(s[i]) >= 0) f4 = true;
            }
            ct += f1 ? 0 : 1;
            ct += f2 ? 0 : 1;
            ct += f3 ? 0 : 1;
            ct += f4 ? 0 : 1;
            out.println(Math.max(ct, 6 - s.length));
        }

    }

    static class FastReader {
        private InputStream stream;
        private byte[] buf = new byte[8192];
        private int curChar;
        private int pnumChars;
        private FastReader.SpaceCharFilter filter;

        public FastReader(InputStream stream) {
            this.stream = stream;
        }

        private int pread() {
            if (pnumChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= pnumChars) {
                curChar = 0;
                try {
                    pnumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (pnumChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = pread();
            while (isSpaceChar(c))
                c = pread();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = pread();
            }
            int res = 0;
            do {
                if (c == ',') {
                    c = pread();
                }
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = pread();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        private boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        private static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public char nextCharacter() {
            int c = pread();
            while (isSpaceChar(c))
                c = pread();
            return (char) c;
        }

        public char[] nextCharacterArray(int n) {
            char[] chars = new char[n];
            for (int i = 0; i < n; i++) {
                chars[i] = nextCharacter();
            }
            return chars;
        }

        private interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}