Given a list A, let f(A) = [A[0] + A[1], A[0] - A[1]]. Alef makes two programs to compute f(f(\ldots(f(A)))), where the function is composed n times:
\begin{array}{|l|l|}
\hline
\textbf{T_{1}(A, n)} & \textbf{T_{2}(A, n)} \\ \hline
1: \ \textbf{FUNCTION } T_{1}(A, n) & 1: \ \textbf{FUNCTION } T_{2}(A, n) \\
2: \ \quad \textbf{IF } n = 0 & 2: \ \quad \textbf{IF } n = 0 \\
3: \ \quad \quad \quad \textbf{RETURN } A & 3: \ \quad \quad \quad \textbf{RETURN } A \\
4: \ \quad \textbf{ELSE} & 4: \ \quad \textbf{ELSE} \\
5: \ \quad \quad \textbf{RETURN } [T_{1}(A, n - 1)[0] + T_{1}(A, n - 1)[1], &
5: \ \quad \quad B \leftarrow T_{2}(A, n - 1) \\
\quad \quad \quad \quad \quad T_{1}(A, n - 1)[0] - T_{1}(A, n - 1)[1]] &
6: \ \quad \quad \textbf{RETURN } [B[0] + B[1], B[0] - B[1]] \\ \hline
\end{array}
Each time T_{1} or T_{2} is called, Alef has to pay one dollar. How much money does he save by calling T_{2}([13, 37], 4) instead of T_{1}([13, 37], 4)?