import numpy as np
import copy
 
 
if __name__ == '__main__':
  N = int(input())
  action_values = np.array([list(map(int, input().split())) for _ in range(N)]) # [[a1, b1, c1], [a2, b2, c2], ...]
  dp = np.zeros((N+1, 3), dtype=int)
  # print(dp)
  for n in range(N+1):
    if n == 0:
      dp[n, :] = 0
    else:
      for i in range(3):
        dp[n, i] = max([dp[n-1, k] + action_values[n-1, i] for k in range(3) if k != i])
    # print(actions)
  # print(dp)
  print(max(dp[N]))

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MwoxMCA0MCA3MAoyMCA1MCA4MAozMCA2MCA5MA==

3
10 40 70
20 50 80
30 60 90