#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;
const ll mod = 1e9 + 7;
// #include <brawlstars>
// FOR PAIN OR FOR GLORYYY ELLL PRIMOOOOOO

const ll N = 501;
ll dp[2][N * 4][N][2];

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	ll n;
	string s;
	cin >> n >> s;
	reverse(s.begin(), s.end());
	dp[0][n][0][0] = 1;
	ll cur = 0, nxt = 1;
	for(ll i = 0; i < n; i++) {
		memset(dp[nxt], 0, sizeof dp[nxt]);
		for(ll j = 0; j < 4 * n; j++) {
			for(ll k = 0; k < N; k++) {
				if(!dp[cur][j][k][0] && !dp[cur][j][k][1]) continue;
				if(s[i] != '1') dp[nxt][j + 1][k][0] = (dp[nxt][j + 1][k][0] + dp[cur][j][k][0] + dp[cur][j][k][1]) % mod;
				if(s[i] != '0') {
					if(i == n - 1 || i < 2 || k < n + 2 - j) continue;
					ll bk = max(n - j + 3, k);
					dp[nxt][j - 3][bk][1] = (dp[nxt][j - 3][bk][1] + dp[cur][j][k][0]) % mod;
				}
			}
		}
		swap(cur, nxt);
	}
	ll ans = 0;
	for(ll i = 0; i < n; i++) ans = (ans + dp[cur][n][i][0]) % mod;
	cout << ans << "\n";
}