program similis;
var a,b,e,code,number1,number2,number3:integer;
    d:array[1..200] of integer;
    c:string;
begin
readln(a);
for b:= 1 to a do begin
   readln(c);
   val(c[1],number1,code);
   val(c[3]+c[4],number2,code);
   val(c[6]+c[7],number3,code);
if number1=1 then e:=e+1 else e:=e-1;

       if (b=1) and (number1=1) then begin
          d[1]:=number2;
          d[2]:=number3;
          d[2]:=0;
       end;

       if (b=1) and (number1=2) then begin
            d[3]:=number2;
            d[4]:=number3;
            d[3]:=0;
       end;
end;

write(48-d[1]);
end.