#include<iostream>
#include<cstring>
#include<vector>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const int mod = 1e9 + 7;

void add(int &a, int b){
    a += b;
    if (a >= mod) a -= mod;
}

int mul(int a, int b){
    return 1LL * a * b % mod;
}

int dp[5000005][2][11], sum[11];

void conv(int *a, int *b){
    static ULL tmp[11];
    memset(tmp, 0, sizeof tmp);
    for(int i = 0; i <= 10; i++){
        for(int j = 0; i + j <= 10; j++){
            tmp[i + j] += 1ull * a[i] * b[j];
        }
    }
    for(int i = 0; i <= 10; i++) a[i] = tmp[i] % mod;
}

int main(){

#ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("data.out", "w", stdout);
#endif

    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);

    int n, m;
    cin >> n >> m;
    string s;
    cin >> s;
    for(int u = n; u >= 1; u--){
        dp[u][0][0] = 1;
        if (2 * u <= n){
            for(int i = 0; i <= 10; i++){
                dp[u][0][i] = dp[2 * u][0][i] + dp[2 * u][1][i];
                if (dp[u][0][i] >= mod) dp[u][0][i] -= mod;
            }
            if (2 * u + 1 <= n){
                for(int i = 0; i <= 10; i++){
                    sum[i] = dp[2 * u + 1][0][i] + dp[2 * u + 1][1][i];
                }
                conv(dp[u][0], sum);
            }
        }
        if (s[u - 1] == '0'){
            for(int i = 1; i <= 10; i++){
                dp[u][1][i] = 1;
            }
            if (2 * u <= n){
                conv(dp[u][1], dp[2 * u][0]);
                if (2 * u + 1 <= n){
                    conv(dp[u][1], dp[2 * u + 1][0]);
                }
            }
        }
    }
    cout << (dp[1][0][m] + dp[1][1][m]) % mod << '\n';

}