program heaven;
var a:array[1..366] of boolean;
    m,d,i,j,k,n:integer; max:longint;
begin
 fillchar(a,sizeof(a),true);
 assign(input,'heaven.in');
 reset(input);
 assign(output,'heaven.out');
 rewrite(output);
 readln(n);
 for i:=1 to n do
 begin
 readln(m,d);
 for j:=1 to m-1 do
 case j of
 1,3,5,7,8,10,12:k:=k+31;
 2:k:=k+29;
 4,6,9,11:k:=k+30;
 end;
 k:=k+d;
 a[k]:=false;
 k:=0;
 end;
 for i:=1 to 366 do
 if a[i] then begin k:=k+1; if k>max then max:=k; end else k:=0;
 max:=round((max/366)*24*3600);
 writeln(max);
end.