import sys


def get_score(n, nums):
    dp = [[0] * 3 for _ in range(n)]
    dp[0] = nums[0]
    state = [1] * 3
    for i in range(3):
        if nums[0][i] == 0:
            state[i] == -1
    for i in range(1, n):
        state1 = state[:]
        for j in range(3):
            # print(dp, state, nums[i])
            cur_max = dp[i - 1][1]
            cur_idx = 1
            for k in [-1, 0, 1]:
                last_idx = j + k
                if last_idx < 0 or last_idx > 2:
                    continue
                cur_sum = dp[i - 1][last_idx] + state[last_idx] * nums[i][j]
                if cur_sum > cur_max:
                    cur_max = cur_sum
                    cur_idx = last_idx
            dp[i][j] = cur_max
            state1[j] = state[cur_idx]
            if nums[i][j] == 0:
                state1[j] *= -1
        state = state1
    return max(dp[-1])



if __name__ == "__main__":
    n = int(sys.stdin.readline().strip())
    nums = []
    for _ in range(n):
        nums.append(list(map(int, sys.stdin.readline().strip().split())))
    print(get_score(n, nums))

交卷了才调完，没测哈～