Lattice path

A lattice path is a path in a grid or lattice that consists of a sequence of steps between points in the grid. Typically, a lattice path is defined within a two-dimensional square grid, where the points are represented by pairs of non-negative integers \((x, y)\), and the path is composed of steps that move in specific directions. In the most common cases, the steps are restricted to two directions: right (R) and up (U).