#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int MAXN = 110;
long long f[MAXN][MAXN][MAXN];
long long g[MAXN];
char s[MAXN];
int main() {
  int n, x;
  scanf("%d%d%s", &n, &x, s + 1);
  for (int i = 1; i <= n; i++) f[s[i] == '1'][i][i] = 1;
  g[0] = 2;
  g[1] = 2;
  for (int i = 2; i <= x; i++) g[i] = (g[i - 1] * g[i - 2]) % MOD;
  for (int i = 2; i <= x; i++) {
    for (int l = 1; l <= n; l++) {
      for (int r = l; r <= n; r++) {
        if (r == n)
          f[i][l][r] = (f[i][l][r] + f[i - 1][l][r] * g[i - 2] % MOD) % MOD;
        else
          f[i][l][r] = (f[i][l][r] + f[i - 1][l][r]) % MOD;
        if (l == 1)
          f[i][l][r] = (f[i][l][r] + f[i - 2][l][r] * g[i - 1] % MOD) % MOD;
        else
          f[i][l][r] = (f[i][l][r] + f[i - 2][l][r]) % MOD;
        for (int k = l; k <= r - 1; k++)
          f[i][l][r] =
              (f[i][l][r] + f[i - 1][l][k] * f[i - 2][k + 1][r] % MOD) % MOD;
      }
    }
  }
  printf("%lld", f[x][1][n]);
}
