program heaven;
const
  month:array[1..12] of real=(31,29,31,30,31,30,31,31,30,31,30,31);
var
  n,i,j,x,y:integer;
  ss,xx,s:real;
  fin,fout:text;

begin
  assign(fin,'heaven.in');
  reset(fin);
  assign(fout,'heaven.out');
  rewrite(fout);

  readln(fin,n);
  ss:=0;
  for i:=1 to n do
  begin
    readln(fin,x,y);
    xx:=0;
    for j:=1 to x-1 do xx:=month[j]+xx;
    ss:=xx+y-ss;
    if ss>s then s:=ss;
  end;
  if s<366-xx then s:=366-xx;
  s:=s-1;
  writeln(fout,s/366*24*3600:0:0);

  close(fin);
  close(fout);
end.