#include <bits/stdc++.h>
using namespace std;
const int maxn = 2007;
const int mod = 1e9 + 7;
int n, m;
int dp[maxn][maxn][2], block[maxn][maxn][2], sum[maxn][maxn][2], vec[maxn][2];
char s[maxn][maxn];
int calc(int u, int v, int w) {
  if (w == 0) {
    for (; vec[v][1] < u; ++vec[v][1]) {
      if (block[vec[v][1] + 1][v][1] <= n - u) break;
    }
    return (sum[u - 1][v][1] - sum[vec[v][1] - 1][v][1] + mod) % mod;
  } else {
    for (; vec[u][0] < v; ++vec[u][0]) {
      if (block[u][vec[u][0] + 1][0] <= m - v) break;
    }
    return (sum[u][v - 1][0] - sum[u][vec[u][0] - 1][0] + mod) % mod;
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0), cout.tie(0);
  cin >> n >> m;
  if (n == 1 && m == 1) {
    cout << 1 << endl;
    return 0;
  }
  for (int i = 1; i <= max(n, m); ++i) {
    vec[i][0] = vec[i][1] = 1;
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      cin >> s[i][j];
      if (s[i][j] == 'R') block[i + 1][j + 1][0] = block[i + 1][j + 1][1] = 1;
    }
  }
  for (int i = 0; i <= n; ++i) {
    for (int j = m; j > 0; --j) {
      block[i][j - 1][0] += block[i][j][0];
    }
  }
  for (int j = 0; j <= m; ++j) {
    for (int i = n; i > 0; --i) {
      block[i - 1][j][1] += block[i][j][1];
    }
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      if (i == 0 && j == 0) {
        dp[0][0][0] = dp[0][0][1] = 1;
        sum[1][1][0] = sum[1][1][1] = 1;
        continue;
      }
      dp[i][j][0] = calc(i + 1, j + 1, 0);
      dp[i][j][1] = calc(i + 1, j + 1, 1);
      sum[i + 1][j + 1][0] = (sum[i + 1][j][0] + dp[i][j][0]) % mod;
      sum[i + 1][j + 1][1] = (sum[i][j + 1][1] + dp[i][j][1]) % mod;
    }
  }
  printf("%d\n", (dp[n - 1][m - 1][0] + dp[n - 1][m - 1][1]) % mod);
  return 0;
}
