n=gets.to_i
dp=Array.new(n+1){[]}
dp[0]=[0,0,0]
n.times do |i|
  h=gets.split.map &:to_i
  dp[i+1][0]=h[0]+[dp[i][1],dp[i][2]].max
  dp[i+1][1]=h[1]+[dp[i][0],dp[i][2]].max
  dp[i+1][2]=h[2]+[dp[i][0],dp[i][1]].max
end
p dp[n].max