#include <bits/stdc++.h>
using namespace std;

#define Gene template< class
#define Rics printer& operator,
Gene c> struct rge{c b, e;};
Gene c> rge<c> range(c i, c j){ return {i, j};}
struct printer{
    ~printer(){cerr<<endl;}
    Gene c >Rics(c x){ cerr<<boolalpha<<x; return *this;}
    Rics(string x){cerr<<x;return *this;}
    Gene c, class d >Rics(pair<c, d> x){ return *this,"(",x.first,", ",x.second,")";}
    Gene ... d, Gene ...> class c >Rics(c<d...> x){ return *this, range(begin(x), end(x));}
    Gene c >Rics(rge<c> x){
        *this,"["; for(auto it = x.b; it != x.e; ++it)
            *this,(it==x.b?"":", "),*it; return *this,"]";}
};
#define debug() cerr<<"LINE "<<__LINE__<<" >> ", printer()
#define dbg(x) "[",#x,": ",(x),"] "
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int my_rand(int l, int r) {
    return uniform_int_distribution<int>(l, r) (rng);
}

const int N = 5e6+10, M = 20;
const int mod = 1e9+7;

int C[M][M];
int dp[N][2][11];

int main() {
//    freopen("in.txt", "r", stdin);
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, m;
    cin >> n >> m;
    string s;
    cin >> s;
    s = "$" + s;

    vector<int> sub(n+1);

    for(int u = n; u >= 1; u--) {
        vector<int> ways(m+1);
        dp[u][0][0] = 1;
        if(s[u] == '0') dp[u][1][1] = 1;
        sub[u] = 1;
        for(int v : {2*u, 2*u+1}) {
            if(v > n) continue;
            vector<int> newDp0(m+1), newDp1(m+1);
            for(int x = 0; x <= m && x <= sub[u]; x++) {
                for(int y = 0; x+y <= m && y <= sub[v]; y++) {
                    newDp0[x+y] += 1ll*dp[u][0][x]*(dp[v][0][y]+dp[v][1][y])%mod;
                    newDp1[x+y] += 1ll*dp[u][1][x]*dp[v][0][y]%mod;
                    if(newDp0[x+y] >= mod) newDp0[x+y] -= mod;
                    if(newDp1[x+y] >= mod) newDp1[x+y] -= mod;
                }
            }
            sub[u] += sub[v];
            for(int k = 0; k <= m; k++) dp[u][0][k] = newDp0[k], dp[u][1][k] = newDp1[k];
        }
//        debug(), dbg(dp[u]);
    }

    for(int i = 0; i < M; i++) {
        C[i][0] = C[i][i] = 1;
        for(int j = 1; j < i; j++) {
            C[i][j] = (C[i-1][j]+C[i-1][j-1])%mod;
        }
    }

    int totalWays = 0;

    for(int k = 1; k <= m; k++) {
        int ways = (dp[1][0][k]+dp[1][1][k])%mod;
        ways = 1ll*ways*C[m-1][k-1]%mod;
        totalWays += ways;
        totalWays %= mod;
    }
    cout << totalWays << endl;

}