n = gets.to_i
abc = gets.split.map(&:to_i)
dp=Array.new(n){ Array.new(3) }
dp[0][0] = abc[0]
dp[0][1] = abc[1]
dp[0][2] = abc[2]

for i in 1...n
  abc = gets.split.map(&:to_i)
  dp[i][0] = [dp[i-1][1],dp[i-1][2]].max + abc[0]
  dp[i][1] = [dp[i-1][2],dp[i-1][0]].max + abc[1]
  dp[i][2] = [dp[i-1][0],dp[i-1][1]].max + abc[2]
end
p dp[n-1].max
