

function Main(input) {
  input = input.split("\n");
  var N = parseInt(input[0]);
  var a = new Array(N);
  var b = new Array(N);
  var c = new Array(N);
  var maxs = new Array(3);
  for(var i=0;i<3;i++){
    var maxsub=new Array(N).fill(0);
    maxs[i]=maxsub;
  }
  for(var i=0;i<N;i++){
    var tmp = input[i+1].split(" ");
    a[i]=parseInt(tmp[0]);
    b[i]=parseInt(tmp[1]);
    c[i]=parseInt(tmp[2]);
    for(var j=0;j<3;j++){
      if(i==0){
        maxs[j][i]=parseInt(tmp[j]);
      }else{
        if(j==0){
          maxs[1][i]=Math.max(maxs[1][i],maxs[0][i-1]+b[i]);
          maxs[2][i]=Math.max(maxs[2][i],maxs[0][i-1]+c[i]);
        }else if(j==1){
          maxs[0][i]=Math.max(maxs[0][i],maxs[1][i-1]+a[i]);
          maxs[2][i]=Math.max(maxs[2][i],maxs[1][i-1]+c[i]);
        }else{
          maxs[0][i]=Math.max(maxs[0][i],maxs[2][i-1]+a[i]);
          maxs[1][i]=Math.max(maxs[1][i],maxs[2][i-1]+b[i]);
        }
      }
    }
  }
  var ans = Math.max(maxs[0][N-1],maxs[1][N-1],maxs[2][N-1]);
  console.log('%s', ans);
  return ans;
}
// "実行する"ボタンを押した時に実行される関数 (デバッグ用)
function debug(n){
  var input = document.getElementById("input"+n).value;
  var ans=Main(input);
  var result="WA";
  if(ans==document.getElementById("output"+n).value.split("\n")[0]){
    result="AC";
  }
  document.getElementById("result"+n).innerHTML=result;
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));