#include #include using namespace std; using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; using mint = modint998244353; const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } // combination mod prime // https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619 struct combination { vector fact, ifact; combination(int n) :fact(n + 1), ifact(n + 1) { assert(n < mod); fact[0] = 1; for (int i = 1; i <= n; ++i) fact[i] = fact[i - 1] * i; ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) ifact[i - 1] = ifact[i] * i; } mint operator()(int n, int k) { return com(n, k); } mint com(int n, int k) { //負の二項係数を考慮する場合にコメントアウトを外す //if (n < 0) return com(-n, k) * (k % 2 ? -1 : 1); if (k < 0 || k > n) return 0; return fact[n] * ifact[k] * ifact[n - k]; } mint inv(int n, int k) { //if (n < 0) return inv(-n, k) * (k % 2 ? -1 : 1); if (k < 0 || k > n) return 0; return ifact[n] * fact[k] * fact[n - k]; } mint p(int n, int k) { return fact[n] * ifact[n - k]; } }c(200005); vector> mul(vector>&A, vector>&B) { vector> C(A.size(), vector(B[0].size())); rep(i, A.size()) rep(j, B[0].size()) rep(k, A[0].size()) C[i][j] += A[i][k] * B[k][j]; //rep(i, A.size()) rep(j, B[0].size()) rep(k, A[0].size()) C[i][j] += A[i][k] & B[k][j]; return C; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); string s; cin >> s; int k; cin >> k; int sz = s.size() / 2; vector> mans(sz + 1, vector(sz + 1)); vector> mpow(sz + 1, vector(sz + 1)); mans[0][0] = 1; rep(i, sz + 1) { mpow[i][i] = sz * (2 * sz - 1) - i * i - (sz - i)*(sz - i); if (0 < i) { mpow[i - 1][i] = i * i; } if (i < sz) { mpow[i + 1][i] = (sz - i)*(sz - i); } } int copyk = k; while (copyk > 0) { if (1 == copyk % 2) mans = mul(mpow, mans); copyk /= 2; mpow = mul(mpow, mpow); } vector>> dp(2 * sz + 1, vector>(2 * sz + 5, vector(sz + 5))); dp[0][0][0] = 1; for (int i = 0; i < 2 * sz; ++i) { for (int j = 0; j <= 2 * sz; ++j) { for (int k = 0; k <= sz; ++k) { if (s[i] == '(') { dp[i + 1][j + 1][k] += dp[i][j][k]; if (0 < j) { dp[i + 1][j - 1][k + 1] += dp[i][j][k]; } } else { dp[i + 1][j + 1][k] += dp[i][j][k]; if (0 < j) { dp[i + 1][j - 1][k] += dp[i][j][k]; } } } } } mint ans = 0; rep(i, sz + 1) { ans += dp[2 * sz][0][i] * mans[i][0] / (c(sz, i) *c(sz, i)); } cout << ans.val() << endl; return 0; }