import java.util.Scanner ;
public class Xor_rokicki {
   static final long MOD = 1000000007 ;
   static long[][] mul(long[][] a, long[][] b) {
      int n = a.length ;
      long[][] r = new long[n][n] ;
      for (int i=0; i<n; i++)
         for (int j=0; j<n; j++) {
            long sum = 0 ;
            for (int k=0; k<n; k++)
               sum = (sum + a[i][k] * b[k][j]) % MOD ;
            r[i][j] = sum ;
         }
      return r ;
   }
   public static void main(String[] args) throws Exception {
      int T, N, K ;
      String S ;
      Scanner sc = new Scanner(System.in) ;
         N = sc.nextInt() ;
         K = sc.nextInt() ;
         S = sc.next() ;
         int n = 1<<N ; // the size of our matrix
         long a0[][] = new long[n][n] ;
         long a1[][] = new long[n][n] ;
         long a[][] = a0 ;
         for (int k=0; k<2; k++, a = a1) {
            for (int src=0; src<n; src++) {
               for (int dst=0; dst<n; dst++) {
                  if ((dst & ~src) != 0) // can't recombine groups
                     continue ;
                  int val = k ;
                  int forceone = 0 ;
                  int forcezero = 0 ;
                  int evensets = 0 ;
                  int oddsets = 0 ;
                  int mcount = 0 ;
                  boolean fail = false ;
                  for (int i=N-1; i>=0; i--) {
                     if (((src >> i) & 1) == 0 && ((dst >> i) & 1) == 0) {
                        if (val == 0)
                           forcezero += mcount ;
                        else if (val == 1)
                           forceone += mcount ;
                        else if ((mcount & 1) == 0)
                           evensets++ ;
                        else
                           oddsets++ ;
                        mcount = 1 ;
                        val = -1 ;
                     } else if (((src >> i) & 1) == 1 && ((dst >> i) & 1) == 1) {
                        mcount++ ; // all equal
                     } else {
                        if (val == 0) {
                           fail = true ;
                        } else if (val == 1 || val == -1) {
                           forceone += mcount ;
                           val = 0 ;
                        }
                        mcount = 1 ;
                     }
                  }
                  if (val == 0)
                     forcezero += mcount ;
                  else if (val == 1)
                     forceone += mcount ;
                  else if ((mcount & 1) == 0)
                     evensets++ ;
                  else
                     oddsets++ ;
                  if (fail)
                     continue ;
                  int reqparity = forceone & 1 ;
                  int res = 1 ;
                  if (oddsets == 0)
                     res = (1 - reqparity) << evensets ;
                  else
                     res = 1 << ((evensets + oddsets) - 1) ;
                  a[src][dst] = res ;
               }
            }
         }
         long st[][] = new long[n][n] ;
         for (int i=0; i<n; i++)
            st[i][i] = 1 ;
         for (int i=0; i<S.length(); i++)
            if (S.charAt(i) == '0')
               st = mul(st, a0) ;
            else
               st = mul(st, a1) ;
         long r[][] = new long[n][n] ;
         for (int i=0; i<n; i++)
            r[i][i] = 1 ;
         while (K > 0) {
            if ((K & 1) == 1)
               r = mul(r, st) ;
            st = mul(st, st) ;
            K >>= 1 ;
         }
         System.out.println(r[n-1][0]) ;
      }
}