A sequence is defined as special if it contains at least one $0$, followed by at least one $1$, followed by at least one $2$.

Given an integer array nums, return the number of distinct special subsequences modulo $10^9 + 7$.

Note: A subsequence is formed by deleting zero or more elements from an array without altering the relative order of the remaining elements. Two subsequences are considered distinct if they are formed using different sets of indices.

Constraints:

• $1 \leq$ nums.length $\leq 10^5$

• $0 \leq$ nums[i] $\leq 2$

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