uses math;
var n,i,j,m:longint; a,b,c,l1,l2,l3:array[1..1000000]of longint;
begin
readln(n);
for i:=1 to n do readln(a[i],b[i],c[i]);
for i:=n downto 1 do
begin
l1[i]:=a[i];
l2[i]:=b[i];
l3[i]:=c[i];
j:=i+1;
if a[i]+max(l2[j],l3[j])>l1[i] then l1[i]:=a[i]+max(l2[j],l3[j]);
if b[i]+max(l1[j],l3[j])>l2[i] then l2[i]:=b[i]+max(l1[j],l3[j]);
if c[i]+max(l1[j],l2[j])>l3[i] then l3[i]:=c[i]+max(l1[j],l2[j]);
m:=max(max(l1[i],l2[i]),l3[i]);
end;
writeln(m);
end.
