Nephren has never been fond of long farewells. Before Chtholly leaves for her next mission, she says nothing and begins preparing a small ribbon for her instead. She places (n) glass beads in a row on the table before threading them onto the ribbon. Each bead is either white or black. A binary(^{\text{∗}}) string (s) represents their colors: the character (\mathtt{0}) represents a white bead, and the character (\mathtt{1}) represents a black bead. To make the arrangement less ordinary, Nephren turns it into a small game. She can perform the following operation any number of times (possibly zero): Choose two indices (l) and (r) ((1 \le l \le r \le n)) such that (s_l=s_r) in the current string, and reverse(^{\text{†}}) the substring (s_l s_{l+1}\ldots s_r). For example, if (s=\mathtt{00110}), Nephren may choose (l=1) and (r=5), since (s_1=s_5=\mathtt{0}). After the operation, the string becomes (\mathtt{01100}). Determine the number of different binary strings that can be obtained from (s). Since this number may be large, output it modulo (998\,244\,353). (^{\text{∗}})A binary string is a string where each character is either (\mathtt 0) or (\mathtt 1). (^{\text{†}})To reverse a substring (s_l s_{l+1}\ldots s_r) means to replace it with (s_r s_{r-1}\ldots s_l). Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 10^4)). The description of the test cases follows. The first line of each test case contains one integer (n) ((1 \le n \le 10^6)) — the number of beads. The second line contains a binary string (s) of length (n), describing the colors of the beads. It is guaranteed that the sum of (n) over all test cases does not exceed (10^6). For each test case, output a single integer — the number of different binary strings that can be obtained from (s), modulo $$$998\,244\,353$$