#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
template <typename T>
struct modular {
  constexpr modular() : val(0) {}
  constexpr modular(const modular<T>& _m) : val(_m.val) {}
  template <typename U>
  constexpr modular(const U& _r = U()) {
    val = -MOD <= _r && _r < MOD ? _r : _r % MOD;
    if (val < 0) {
      val += MOD;
    }
  }
  const T operator()() { return val; }
  template <typename U>
  explicit operator U() const {
    return static_cast<U>(val);
  }
  modular<T>& operator+=(const modular<T>& _m) {
    if ((val += _m.val) >= MOD) {
      val -= MOD;
    }
    return *this;
  }
  modular<T>& operator-=(const modular<T>& _m) {
    if ((val -= _m.val) < 0) {
      val += MOD;
    }
    return *this;
  }
  modular<T>& operator*=(const modular<T>& _m) {
    val = modular<T>(static_cast<int64_t>(val) * static_cast<int64_t>(_m.val))
              .val;
    return *this;
  }
  modular<T>& operator/=(const modular<T>& _m) {
    T a = _m.val, b = MOD, u = 0, v = 1;
    while (a != 0) {
      T q = b / a;
      b -= q * a;
      swap(a, b);
      u -= q * v;
      swap(u, v);
    }
    return *this *= u;
  }
  modular<T>& operator=(const modular<T>& _m) {
    val = _m.val;
    return *this;
  }
  template <typename U>
  modular<T>& operator+=(const U& _r) {
    return *this += modular<T>(_r);
  }
  template <typename U>
  modular<T>& operator-=(const U& _r) {
    return *this -= modular<T>(_r);
  }
  template <typename U>
  modular<T>& operator*=(const U& _r) {
    return *this *= modular<T>(_r);
  }
  template <typename U>
  modular<T>& operator/=(const U& _r) {
    return *this /= modular<T>(_r);
  }
  template <typename U>
  modular<T>& operator=(const U& _r) {
    val = modular<T>(_r).val;
    return *this;
  }
  modular<T> operator-() { return modular<T>(-val); }
  template <typename U>
  friend bool operator==(const modular<U>&, const modular<U>&);
  friend std::istream& operator>>(std::istream& os, modular<T>& _m) {
    os >> _m.val;
    _m *= 1;
    return os;
  }
  friend std::ostream& operator<<(std::ostream& os, const modular<T>& _m) {
    return os << _m.val;
  }
  template <typename U>
  modular<T> exp(U e) {
    modular<T> res = 1;
    modular<T> b = val;
    if (e < 0) {
      b = 1 / b;
      e *= -1;
    }
    for (; e; e >>= 1) {
      if (e & 1) {
        res *= b;
      }
      b *= b;
    }
    return res;
  }

 private:
  T val;
};
template <typename T>
inline modular<T> operator+(const modular<T>& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) += _rhs;
}
template <typename T, typename U>
inline modular<T> operator+(const modular<T>& _lhs, const U& _rhs) {
  return modular<T>(_lhs) += _rhs;
}
template <typename T, typename U>
inline modular<T> operator+(const U& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) += _rhs;
}
template <typename T>
inline modular<T> operator-(const modular<T>& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) -= _rhs;
}
template <typename T, typename U>
inline modular<T> operator-(const modular<T>& _lhs, const U& _rhs) {
  return modular<T>(_lhs) -= _rhs;
}
template <typename T, typename U>
inline modular<T> operator-(const U& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) -= _rhs;
}
template <typename T>
inline modular<T> operator*(const modular<T>& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) *= _rhs;
}
template <typename T, typename U>
inline modular<T> operator*(const modular<T>& _lhs, const U& _rhs) {
  return modular<T>(_lhs) *= _rhs;
}
template <typename T, typename U>
inline modular<T> operator*(const U& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) *= _rhs;
}
template <typename T>
inline modular<T> operator/(const modular<T>& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) /= _rhs;
}
template <typename T, typename U>
inline modular<T> operator/(const modular<T>& _lhs, const U& _rhs) {
  return modular<T>(_lhs) /= _rhs;
}
template <typename T, typename U>
inline modular<T> operator/(const U& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) /= _rhs;
}
template <typename T>
inline bool operator==(const modular<T>& _lhs, const modular<T>& _rhs) {
  return _lhs.val == _rhs.val;
}
template <typename T, typename U>
inline bool operator==(const modular<T>& _lhs, const U& _rhs) {
  return _lhs == modular<T>(_rhs);
}
template <typename T, typename U>
inline bool operator==(const U& _lhs, const modular<T>& _rhs) {
  return modular<T>(_lhs) == _rhs;
}
template <typename T>
inline bool operator!=(const modular<T>& _lhs, const modular<T>& _rhs) {
  return !(_lhs == _rhs);
}
template <typename T, typename U>
inline bool operator!=(const modular<T>& _lhs, const U& _rhs) {
  return !(_lhs == _rhs);
}
template <typename T, typename U>
inline bool operator!=(const U& _lhs, const modular<T>& _rhs) {
  return !(_lhs == _rhs);
}
const int N = 110;
modular<int> dp[N][N][N];
modular<int> fibo[N];
void solve() {
  int n, m;
  cin >> n >> m;
  string s;
  cin >> s;
  fibo[0] = 2;
  fibo[1] = 2;
  for (int i = 2; i < N; i++) {
    fibo[i] = fibo[i - 1] * fibo[i - 2];
  }
  for (int x = 0; x < N; x++) {
    for (int i = 0; i <= n; i++) {
      dp[i][i][x] = 1;
    }
  }
  for (int i = 0; i < n; i++) {
    if (s[i] == '0')
      dp[i][i + 1][0] = 1;
    else
      dp[i][i + 1][1] = 1;
  }
  for (int x = 2; x <= m; x++) {
    for (int l = 0; l < n; l++) {
      for (int r = l + 1; r <= n; r++) {
        for (int k = l; k <= r; k++) {
          dp[l][r][x] += dp[l][k][x - 1] * dp[k][r][x - 2] *
                         (k == 0 ? fibo[x - 1] : 1) *
                         (k == n ? fibo[x - 2] : 1);
        }
      }
    }
  }
  cout << dp[0][n][m];
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
  cout << endl;
}
