program Fibonacci_sequence;

var
  i, Fi, j, Fj, n, t, x, y : longint;
  P, Q : array [-1..5000] of longint;

procedure Answer (What : longint);

begin
  Write (What);
  {$IFDEF TPDEBUG}WriteLn;{$ENDIF}
  Halt;
end;

begin
  Read (i, Fi, j, Fj, n);
  if i > j then begin
    t := i; i := j; j := t;
    t := Fi; Fi := Fj; Fj := t;
  end;
  Q [0] := Fi; Q [1] := 0;
  P [0] := 0; P [1] := 1;
  t := j - i;
  for x := 2 to t do begin
    P [x] := P [x - 1] + P [x - 2];
    Q [x] := Q [x - 1] + Q [x - 2];
  end;
  y := (Fj - Q [t]) div P [t];
  if (n >= i) and (n <= j) then Answer (Q [n - i] + P [n - i] * y);
  if (n < i) then begin
    P [-1] := P [1]; Q [-1] := Q [1];
    for x := 1 to i - n do begin
      P [x] := P [x - 2] - P [x - 1];
      Q [x] := Q [x - 2] - Q [x - 1];
    end;
    Answer (Q [i - n] + P [i - n] * y);
  end;
  if (n > j) then begin
    P [-1] := P [j - i - 1]; P [0] := P [j - i];
    Q [-1] := Q [j - i - 1]; Q [0] := Q [j - i];
    for x := 1 to n - j do begin
      P [x] := P [x - 1] + P [x - 2];
      Q [x] := Q [x - 1] + Q [x - 2];
    end;
    Answer (Q [n - j] + P [n - j] * y);
  end;
end.