Solution

#include <iostream>
#include <algorithm>
#include <cstdio>
using namespace std;
#define MOD 1000000007

int N;
long long p = 500000004LL;
char A[2005][2005];
char B[2005][2005];
int r[2005][2005];
int b[2005][2005];
int psr[2005][2005];
int psb[2005][2005];

int main()
{
	cin >> N;
	for (int i = 0; i < N; i++)
		cin >> (A[i + 1] + 1);
	for (int i = 2; i <= N + 1; i++)
		if (A[i - 1][1] == '.')
			b[i][0] = psb[i][0] = p;
	for (int j = 1; j <= N; j++)
		if (A[1][j] == '.')
			r[1][j] = psr[1][j] = p;
	for (int i = 2; i <= N + 1; i++)
		for (int j = 1; j <= N; j++)
		{
			if (A[i][j] == '.')
			{
				r[i][j] = (p * psb[i][j - 1]) % MOD;
			}
			if (A[i - 1][j + 1] == '.')
			{
				b[i][j] = (p * psr[i - 1][j]) % MOD;
			}
			psr[i][j] = (psr[i - 1][j] + r[i][j]) % MOD;
			psb[i][j] = (psb[i][j - 1] + b[i][j]) % MOD;
		}
	int ans = (psr[N][N] + psb[N + 1][N]) % MOD;
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= N; j++)
			if (A[i][j] == '.')
				ans = (2LL * ans) % MOD;
	cout << ans << '\n';
}