program heaven;
var
  n,i,j,a,b,m,max,temp:longint;
  mon:array[1..12]of longint;
  day:array[1..366]of 0..1;
begin
  assign(input,'heaven.in');
  assign(output,'heaven.out');
  reset(input);
  rewrite(output);
  mon[1]:=31;
  mon[2]:=29;
  mon[3]:=31;
  mon[4]:=30;
  mon[5]:=31;
  mon[6]:=30;
  mon[7]:=31;
  mon[8]:=31;
  mon[9]:=30;
  mon[10]:=31;
  mon[11]:=30;
  mon[12]:=31;
  readln(n);
  fillchar(day,sizeof(day),0);
  for i:=1 to n do
  begin
    readln(a,b);
    m:=0;
    for j:=1 to a-1 do
      m:=m+mon[j];
    m:=m+b;
    day[m]:=1;
  end;
  max:=0;
  temp:=0;
  for i:=1 to 366 do
  begin
    if day[i]=0 then temp:=temp+1 else begin
      if max<temp then max:=temp;
      temp:=0;
    end;
  end;
  if (max/366*24*60*60)-trunc(max/366*24*60*60)>=0.5 then writeln(trunc(max/366*24*60*60)+1) else
    writeln(trunc(max/366*24*60*60));
  close(input);
  close(output);
end.