#include <bits/stdc++.h>
using namespace std;
int N, M;
string s[2020];
long long dp[2020][2020][2], C[2020][2020][2], S[2020][2020][2];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> N >> M;
  for (int i = 1; i <= N; i++) {
    cin >> s[i];
    s[i] = '#' + s[i];
  }
  for (int i = N; i >= 1; i--)
    for (int j = M; j >= 1; j--) {
      C[i][j][0] = C[i][j + 1][0] + (s[i][j] == 'R');
      C[i][j][1] = C[i + 1][j][1] + (s[i][j] == 'R');
      if (i == N && j == M) {
        dp[i][j][0] = dp[i][j][1] = 1;
      } else {
        int r = M - C[i][j + 1][0];
        int d = N - C[i + 1][j][1];
        dp[i][j][0] = (S[i][j + 1][0] - S[i][r + 1][0]) % 1000000007;
        dp[i][j][1] = (S[i + 1][j][1] - S[d + 1][j][1]) % 1000000007;
      }
      S[i][j][0] = (S[i][j + 1][0] + dp[i][j][1]) % 1000000007;
      S[i][j][1] = (S[i + 1][j][1] + dp[i][j][0]) % 1000000007;
    }
  long long res = dp[1][1][0] + dp[1][1][1];
  if (N == 1 && M == 1) res = 1;
  res %= 1000000007;
  res += 1000000007;
  res %= 1000000007;
  printf("%lld", res);
  return 0;
}
