program Acm_1070;
  var
    t1,t2:real;
    a,b,c,d:longint;
    i,te:longint;
    t:array[1..2] of longint;
  begin
    for i:=1 to 2 do
      begin
        readln(t1,t2); t1:=t1*100; t2:=t2*100;
        a:=round(t1); b:=round(t2);
        c:=a mod 100; d:=b mod 100; a:=a div 100; b:=b div
100;
        t[i]:=(b*60+d)-(a*60+c);
        if t[i]<=0 then t[i]:=t[i]+1440
      end;
    te:=abs(t[1]-t[2]);
    for i:=-10 to 10 do
      if abs(te+i) mod 120=0 then
        begin
          writeln(abs(te+i) div 120);
          halt
        end
  end.