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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