I always got wa, but i don't know why.
here's my program(very simple, perhaps i haven't understood
the task perfectly):
Const
    InFile    = '1070.in';

Var
    s1 , e1 ,
    s2 , e2    : real;

procedure readnum_sub(var n : real);
var
    c    : char;
begin
    n := 0;
    read(c);
    while not (c in ['0'..'9']) do read(c);
    while (not eoln) and (c in ['0'..'9']) do
      begin
          n := n * 10 + ord(c) - ord('0');
          read(c);
      end;
    if c in ['0'..'9'] then
      n := n * 10 + ord(c) - ord('0');
end;

procedure readnum(var n : real);
var
    a , b    : real;
begin
    readnum_sub(a);
    readnum_sub(b);
    n := a + b / 60;
end;

procedure init;
begin
    assign(INPUT , InFile); ReSet(INPUT);
      readnum(s1); readnum(e1);
      readln;
      readnum(s2); readnum(e2);
{    Close(INPUT);}
end;

procedure work;
var
    i    : integer;
    temp , t2    : real;
begin
    for i := 5 downto -5 do
      if i <> 0 then
      begin
          temp := e1 + i - s1;
          while temp < 0 do
            temp := temp + 24;
          if temp > 6 then
            continue;
          t2 := s2 + i + temp;
          if t2 >= 24 then
            t2 := t2 - 24;
          if abs(t2 - e2) <= 1 / 6 then
            begin
                writeln(abs(i));
                exit;
            end;
      end;
end;

Begin
    init;
    work;
End.