Problem: Recently Vasya got interested in finding extra-terrestrial intelligence. He made a simple extra-terrestrial signals’ receiver and was keeping a record of the signals for n days in a row. Each of those n days Vasya wrote a 1 in his notebook if he had received a signal that day and a 0 if he hadn’t. Vasya thinks that he has found extra-terrestrial intelligence if there is a system in the way the signals has been received, i.e. if all the intervals between successive signals are equal. Otherwise, Vasya thinks that the signals were sent by some stupid aliens no one cares about. Help Vasya to deduce from the information given by the receiver if he has found extra-terrestrial intelligence or not.

Input

The first line contains integer n (3 ≤ n ≤ 100) — amount of days during which Vasya checked if there were any signals. The second line contains n characters 1 or 0 — the record Vasya kept each of those n days. It’s guaranteed that the given record sequence contains at least three 1s.

Output

If Vasya has found extra-terrestrial intelligence, output YES, otherwise output NO.

Examples

Input

8
00111000


Output

YES


Input

7
1001011


Output

NO


Input

7
1010100


Output

YES

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Pranay2516
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream;
        try {
            inputStream = new FileInputStream("input.txt");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        OutputStream outputStream;
        try {
            outputStream = new FileOutputStream("output.txt");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        FastReader in = new FastReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        AExtraTerrestrialIntelligence solver = new AExtraTerrestrialIntelligence();
        solver.solve(1, in, out);
        out.close();
    }

    static class AExtraTerrestrialIntelligence {
        public void solve(int testNumber, FastReader in, PrintWriter out) {
            int n = in.nextInt(), d = 0;
            char[] c = in.next().toCharArray();
            ArrayList<Integer> a = new ArrayList<>();
            for (int i = 0; i < n; ++i) {
                if (c[i] == '1') {
                    a.add(i);
                }
            }
            for (int i = 0; i < a.size() - 1; ++i) {
                if (i == 0) {
                    d = a.get(i + 1) - a.get(i);
                    continue;
                }
                if (a.get(i + 1) - a.get(i) != d) {
                    out.println("NO");
                    return;
                }
            }
            out.println("YES");
        }

    }

    static class FastReader {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private FastReader.SpaceCharFilter filter;

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

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

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

        public String next() {
            int c = read();
            while (isSpaceChar(c)) c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

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

        }

    }
}