AC100,唯一一道ac的，尴尬

import sys
def InputFunc():
    n = int(input())
    A = []
    for i in range(n):
        tmp = list(map(int, input().strip().split()))
        A.append(tmp)
    return n, A

def main():
    n, A = InputFunc()
    if n == 0:
        print(0)
        return 0
    max_value = sys.maxsize
    dp = [[max_value]*2 for _ in range(n)]
    for i in range(n):
        if i == 0:
            dp[i][1] = A[i][1]
            dp[i][0] = A[i][0]+A[i][2]
        else:
            dp[i][0] = min(dp[i-1][0]+A[i][0], dp[i-1][1] + A[i][0] + A[i][2])
            dp[i][1] = min(dp[i-1][1]+A[i][1], dp[i-1][0] + A[i][1] + A[i][2])
    print (min(dp[n-1][0], dp[n-1][1]))


if __name__ == "__main__":
    main()