Let \(f : [-1, 1] \to R\) be defined as \(f(x) = ax^2 + bx + c\) for all \(x \in [-1, 1]\), where \(a, b, c \in R\) such that \(f(-1) = 2\), \(f'(-1) = 1\) for \(x \in (-1, 1)\) the maximum value of \(f''(x)\) is \(\frac12\). If \(f(x) \le \alpha\), \(x \in [-1, 1]\), then the least value of \(\alpha\) is equal to _________.