#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int mxN = 110;
string s;
long long dp[mxN][mxN][mxN];
int inv2;
long long F[mxN];
long long pow_mod(long long base, long long power) {
  long long res = 1;
  while (power) {
    if (power & 1) res = res * base % mod;
    base = base * base % mod;
    power >>= 1;
  }
  return res;
}
void get(int X) {
  dp[X][s.size()][s.size()] = 1;
  dp[X][0][0] = 1;
  if (X == 0) {
    for (int i = 0; i < (int)s.size(); i++) {
      if (i) dp[X][i][i] = inv2;
      if (s[i] == '0') dp[X][i][i + 1] = inv2;
    }
    return;
  }
  if (X == 1) {
    for (int i = 0; i < (int)s.size(); i++) {
      if (i) dp[X][i][i] = inv2;
      if (s[i] == '1') dp[X][i][i + 1] = inv2;
    }
    return;
  }
  for (int i = 0; i < (int)s.size(); i++) {
    for (int j = i; j <= (int)s.size(); j++) {
      for (int k = i; k <= j; k++) {
        dp[X][i][j] = (dp[X][i][j] + dp[X - 1][i][k] * dp[X - 2][k][j]) % mod;
      }
      dp[X][0][0] = 1;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  F[0] = F[1] = 1;
  for (long long i = 2; i < mxN; i++) F[i] = (F[i - 1] + F[i - 2]) % (mod - 1);
  int N, X;
  cin >> N >> X >> s;
  inv2 = pow_mod(2, mod - 2);
  for (int i = 0; i <= X; i++) get(i);
  cout << (pow_mod(2, F[X]) * dp[X][0][s.size()]) % mod << '\n';
  return 0;
}
