import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.TreeSet;
 
 
 
public class Main {
  public static void main(String[] args) {
    InputReader sc = new InputReader(System.in);
 
    int n = sc.nextInt();
    int[][] happies = new int[n+1][3];
    happies[0][0] = 0;
    happies[0][1] = 0;
    happies[0][2] = 0;

    for(int i = 0; i < n; i++){
      int a = sc.nextInt();
      int b = sc.nextInt();
      int c = sc.nextInt();
 
      if(happies[i][0] > happies[i][1]){
        happies[i+1][2] = happies[i][0] + c;
      }else{
        happies[i+1][2] = happies[i][1] + c;        
      }

      if(happies[i][1] > happies[i][2]){
        happies[i+1][0] = happies[i][1] + a;
      }else{
        happies[i+1][0] = happies[i][2] + a;        
      }

      if(happies[i][2] > happies[i][0]){
        happies[i+1][1] = happies[i][2] + b;
      }else{
        happies[i+1][1] = happies[i][0] + b;        
      }

    }
 
    System.out.println(Math.max(Math.max(happies[n][0], happies[n][1]), happies[n][2]));

  }
 
 //ここからテンプレ
  static class InputReader {
      private InputStream stream;
      private byte[] buf = new byte[1024];
      private int curChar;
      private int numChars;
      private SpaceCharFilter filter;
 
      public InputReader(InputStream stream) {
          this.stream = stream;
      }
 
      public int next() {
          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 String nextStr() {
        int c = next();
        while(isSpaceChar(c)){c = next();}
        StringBuffer str = new StringBuffer();
        do{
          str.append((char)c);
          c = next();
        }while(!isSpaceChar(c));
        return str.toString();
      }
 
      public char nextChar() {
        int c = next();
        while(isSpaceChar(c)){c = next();}
        char ret;
        do{
          ret = (char)c;
          c = next();
        }while(!isSpaceChar(c));
        return ret;
      }
 
      public int nextInt() {
          int c = next();
          while (isSpaceChar(c))
              c = next();
          int sgn = 1;
          if (c == '-') {
              sgn = -1;
              c = next();
          }
          int res = 0;
          do {
              if (c < '0' || c > '9')
                  throw new InputMismatchException();
              res *= 10;
              res += c - '0';
              c = next();
          } while (!isSpaceChar(c));
          return res * sgn;
      }
 
      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);
      }
  }
}

Measured memory_bytes: 26068