import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

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

    static class BPath {
        public void solve(int testNumber, InputReader in, OutputWriter out) {

            int[][] g = new int[4][4];

            for (int i = 0; i < 3; i++) {
                int a = in.nextInt();
                int b = in.nextInt();

                a--;
                b--;

                g[a][b] = 1;
                g[b][a] = 1;
            }

            NextPermutation np = new NextPermutation();

            int[] a = new int[4];

            for (int i = 0; i < 4; i++) {
                a[i] = i;
            }

            do {
                boolean poss = true;
                for (int i = 0; i < 3; i++) {
                    if (g[a[i]][a[i + 1]] == 0) {
                        poss = false;
                        break;
                    }
                }

                if (poss) {
                    out.println("YES");
                    return;
                }
            } while ((a = np.nextPermutation(a)) != null);

            out.println("NO");
        }

        class NextPermutation {
            public int[] nextPermutation(int[] nums) {
                if (nums == null || nums.length < 2)
                    return null;

                int p = 0;
                for (int i = nums.length - 2; i >= 0; i--) {
                    if (nums[i] < nums[i + 1]) {
                        p = i;
                        break;
                    }
                }

                int q = 0;
                for (int i = nums.length - 1; i > p; i--) {
                    if (nums[i] > nums[p]) {
                        q = i;
                        break;
                    }
                }

                if (p == 0 && q == 0) {
                    reverse(nums, 0, nums.length - 1);
                    return null;
                }

                int temp = nums[p];
                nums[p] = nums[q];
                nums[q] = temp;

                if (p < nums.length - 1) {
                    reverse(nums, p + 1, nums.length - 1);
                }

                return nums;
            }

            public void reverse(int[] nums, int left, int right) {
                while (left < right) {
                    int temp = nums[left];
                    nums[left] = nums[right];
                    nums[right] = temp;
                    left++;
                    right--;
                }
            }

        }

    }

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

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

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

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

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

        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0) {
                    writer.print(' ');
                }
                writer.print(objects[i]);
            }
        }

        public void println(Object... objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }

    }
}



Measured memory_bytes: 21204