#include <bits/stdc++.h>
using namespace std;
const int N = 105;
const int mod = 1e9 + 7;
int n, x;
string s;
int dp[N][N][N];
int pw[N];
void add(int &x, int y) {
  x += y;
  while (x >= mod) x -= mod;
  while (x < 0) x += mod;
}
int calc(int k, int l, int r) {
  if (l > r) return 1;
  if (k <= 1) return l == r && s[l] == '0' + k;
  int &ans = dp[k][l][r];
  if (ans != -1) return ans;
  ans = 0;
  for (int mid = l - 1; mid <= r; ++mid) {
    int cur = 1LL * calc(k - 1, l, mid) * calc(k - 2, mid + 1, r) % mod;
    if (mid + 1 == l && l == 0) cur = 1LL * cur * pw[k - 1] % mod;
    if (mid == r && r == n - 1) cur = 1LL * cur * pw[k - 2] % mod;
    add(ans, cur);
  }
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> x >> s;
  memset(dp, -1, sizeof dp);
  pw[0] = pw[1] = 2;
  for (int i = 2; i <= x; ++i) pw[i] = 1LL * pw[i - 1] * pw[i - 2] % mod;
  cout << calc(x, 0, n - 1) << endl;
}
