3906. Count Good Integers on a Grid Path

You are given two integers l and r, and a string directions consisting of exactly three 'D' characters and three 'R' characters. For each integer x in the range [l, r] (inclusive), perform the following steps: - If x has fewer than 16 digits, pad it on the left with leading zeros to obtain a 16-digit string. - Place the 16 digits into a 4 × 4 grid in row-major order (the first 4 digits form the