My First Geometry Problem

You are on a $2$-dimensional grid, where you start at $(0, 0)$. You are given a **binary** string $S$ of length $4$ where: - $S_1$ refers to *left* direction; - $S_2$ refers to *right* direction; - $S_3$ refers to *up* direction; - $S_4$ refers to *down* direction. $S_i = 1$ denotes that you are allowed to make a move in the respective direction and vice-versa. Find the number of cells $(x, y)