Let \( S \) be the set of all seven-digit numbers that can be formed using the digits \( 0 \), \( 1 \) and \( 2 \). For example, \( 2210222 \) is in \( S \), but \( 0210222 \) is NOT in \( S \). Then the number of elements \( x \) in \( S \) such that at least one of the digits \( 0 \) and \( 1 \) appears exactly twice in \( x \), is equal to ___________.
