Problem:
Score : 100 points

Problem Statement

Taro's summer vacation starts tomorrow, and he has decided to make plans for it now.

The vacation consists of N days.
For each i (1 \leq i \leq N), Taro will choose one of the following activities and do it on the i-th day:

A: Swim in the sea. Gain a_i points of happiness.

B: Catch bugs in the mountains. Gain b_i points of happiness.

C: Do homework at home. Gain c_i points of happiness.

As Taro gets bored easily, he cannot do the same activities for two or more consecutive days.

Find the maximum possible total points of happiness that Taro gains.

Constraints

All values in input are integers.

1 \leq N \leq 10^5

1 \leq a_i, b_i, c_i \leq 10^4

Input

Input is given from Standard Input in the following format:

N
a_1 b_1 c_1
a_2 b_2 c_2
:
a_N b_N c_N

Output

Print the maximum possible total points of happiness that Taro gains.

Sample Input 1

3
10 40 70
20 50 80
30 60 90

Sample Output 1

210

If Taro does activities in the order C, B, C, he will gain 70 + 50 + 90 = 210 points of happiness.

Sample Input 2

1
100 10 1

Sample Output 2

100

Sample Input 3

7
6 7 8
8 8 3
2 5 2
7 8 6
4 6 8
2 3 4
7 5 1

Sample Output 3

46

Taro should do activities in the order C, A, B, A, C, B, A.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

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

/**
 * Built using CHelper plug-in Actual solution is at the top
 *
 * @author @Ziklon
 */
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);
    CVacation solver = new CVacation();
    solver.solve(1, in, out);
    out.close();
  }

  static class CVacation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int n = in.readInt();
      int[][] array = in.readIntTable(n, 3);
      int dp[][] = new int[2][3];
      ArrayUtils.fill(dp, -1);
      Arrays.fill(dp[0], 0);

      for (int i = 0; i < n; ++i) {
        for (int j = 0; j < 3; ++j)
          for (int k = 0; k < 3; ++k) {
            if (j == k) continue;
            dp[(i + 1) & 1][k] = Math.max(dp[(i + 1) & 1][k], dp[i & 1][j] + array[i][k]);
          }
      }
      out.printLine(ArrayUtils.maxElement(dp[n & 1]));
    }
  }

  static interface IntCollection extends IntStream {
    public int size();
  }

  static interface IntList extends IntReversableCollection {
    public abstract int get(int index);

    public abstract void removeAt(int index);

    public default IntIterator intIterator() {
      return new IntIterator() {
        private int at;
        private boolean removed;

        public int value() {
          if (removed) {
            throw new IllegalStateException();
          }
          return get(at);
        }

        public boolean advance() {
          at++;
          removed = false;
          return isValid();
        }

        public boolean isValid() {
          return !removed && at < size();
        }

        public void remove() {
          removeAt(at);
          at--;
          removed = true;
        }
      };
    }
  }

  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 close() {
      writer.close();
    }

    public void printLine(int i) {
      writer.println(i);
    }
  }

  static interface IntReversableCollection extends IntCollection {}

  static interface IntStream extends Iterable<Integer>, Comparable<IntStream> {
    public IntIterator intIterator();

    public default Iterator<Integer> iterator() {
      return new Iterator<Integer>() {
        private IntIterator it = intIterator();

        public boolean hasNext() {
          return it.isValid();
        }

        public Integer next() {
          int result = it.value();
          it.advance();
          return result;
        }
      };
    }

    public default int compareTo(IntStream c) {
      IntIterator it = intIterator();
      IntIterator jt = c.intIterator();
      while (it.isValid() && jt.isValid()) {
        int i = it.value();
        int j = jt.value();
        if (i < j) {
          return -1;
        } else if (i > j) {
          return 1;
        }
        it.advance();
        jt.advance();
      }
      if (it.isValid()) {
        return 1;
      }
      if (jt.isValid()) {
        return -1;
      }
      return 0;
    }

    public default int max() {
      int result = Integer.MIN_VALUE;
      for (IntIterator it = intIterator(); it.isValid(); it.advance()) {
        int current = it.value();
        if (current > result) {
          result = current;
        }
      }
      return result;
    }
  }

  static class IntArray extends IntAbstractStream implements IntList {
    private int[] data;

    public IntArray(int[] arr) {
      data = arr;
    }

    public int size() {
      return data.length;
    }

    public int get(int at) {
      return data[at];
    }

    public void removeAt(int index) {
      throw new UnsupportedOperationException();
    }
  }

  abstract static class IntAbstractStream implements IntStream {
    public String toString() {
      StringBuilder builder = new StringBuilder();
      boolean first = true;
      for (IntIterator it = intIterator(); it.isValid(); it.advance()) {
        if (first) {
          first = false;
        } else {
          builder.append(' ');
        }
        builder.append(it.value());
      }
      return builder.toString();
    }

    public boolean equals(Object o) {
      if (!(o instanceof IntStream)) {
        return false;
      }
      IntStream c = (IntStream) o;
      IntIterator it = intIterator();
      IntIterator jt = c.intIterator();
      while (it.isValid() && jt.isValid()) {
        if (it.value() != jt.value()) {
          return false;
        }
        it.advance();
        jt.advance();
      }
      return !it.isValid() && !jt.isValid();
    }

    public int hashCode() {
      int result = 0;
      for (IntIterator it = intIterator(); it.isValid(); it.advance()) {
        result *= 31;
        result += it.value();
      }
      return result;
    }
  }

  static class ArrayUtils {
    public static void fill(int[][] array, int value) {
      for (int[] row : array) {
        Arrays.fill(row, value);
      }
    }

    public static int maxElement(int[] array) {
      return new IntArray(array).max();
    }
  }

  static interface IntIterator {
    public int value() throws NoSuchElementException;

    public boolean advance();

    public boolean isValid();
  }

  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 int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

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

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