#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const int FFTMOD = 1007681537;
const int INF = (int)1e9;
const long long LINF = (long long)1e18;
const long double PI = acos((long double)-1);
const long double EPS = 1e-9;
inline long long gcd(long long a, long long b) {
  long long r;
  while (b) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long fpow(long long n, long long k, int p = MOD) {
  long long r = 1;
  for (; k; k >>= 1) {
    if (k & 1) r = r * n % p;
    n = n * n % p;
  }
  return r;
}
template <class T>
inline int chkmin(T& a, const T& val) {
  return val < a ? a = val, 1 : 0;
}
template <class T>
inline int chkmax(T& a, const T& val) {
  return a < val ? a = val, 1 : 0;
}
inline long long isqrt(long long k) {
  long long r = sqrt(k) + 1;
  while (r * r > k) r--;
  return r;
}
inline long long icbrt(long long k) {
  long long r = cbrt(k) + 1;
  while (r * r * r > k) r--;
  return r;
}
inline void addmod(int& a, int val, int p = MOD) {
  if ((a = (a + val)) >= p) a -= p;
}
inline void submod(int& a, int val, int p = MOD) {
  if ((a = (a - val)) < 0) a += p;
}
inline int mult(int a, int b, int p = MOD) { return (long long)a * b % p; }
inline int inv(int a, int p = MOD) { return fpow(a, p - 2, p); }
inline int sign(long double x) { return x < -EPS ? -1 : x > +EPS; }
inline int sign(long double x, long double y) { return sign(x - y); }
const int maxn = 50 + 5;
int n, p;
int c[maxn];
int f[maxn][maxn];
int p2[maxn];
int dp[maxn][maxn][maxn][2];
int calc(int pos, int u, int v, int fa) {
  if (pos == n) return fa == p;
  int& res = dp[pos][u][v][fa];
  if (~res) return res;
  res = 0;
  for (int i = (0); i < (2); ++i) {
    int num = c[pos] == -1 || c[pos] == i;
    if (!num) continue;
    int ar[] = {u, v};
    for (int j = (0); j < (ar[i ^ 1] + 1); ++j) {
      int add = j + 1 & 1;
      ar[i] += add;
      int nfa = fa + j + 1 & 1;
      addmod(res,
             mult(p2[pos - ar[i ^ 1]],
                  mult(f[j][ar[i ^ 1]], calc(pos + 1, ar[0], ar[1], nfa))));
      ar[i] -= add;
    }
  }
  return res;
}
void chemthan() {
  for (int i = (0); i < (maxn); ++i) f[0][i] = 1;
  for (int i = (1); i < (maxn); ++i)
    for (int j = (1); j < (maxn); ++j)
      f[i][j] = (f[i][j - 1] + f[i - 1][j - 1]) % MOD;
  for (int i = (0); i < (maxn); ++i) p2[i] = fpow(2, i);
  cin >> n >> p;
  for (int i = (0); i < (n); ++i) cin >> c[i];
  memset(dp, -1, sizeof(dp));
  cout << calc(0, 0, 0, 0) << "\n";
}
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(0), cin.tie(0);
  if (argc > 1) {
    assert(freopen(argv[1], "r", stdin));
  }
  if (argc > 2) {
    assert(freopen(argv[2], "wb", stdout));
  }
  chemthan();
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
