Problem:
Score : 100 points

Problem Statement

There is a grid with H horizontal rows and W vertical columns.
Let (i, j) denote the square at the i-th row from the top and the j-th column from the left.

For each i and j (1 \leq i \leq H, 1 \leq j \leq W), Square (i, j) is described by a character a_{i, j}.
If a_{i, j} is ., Square (i, j) is an empty square; if a_{i, j} is #, Square (i, j) is a wall square.
It is guaranteed that Squares (1, 1) and (H, W) are empty squares.

Taro will start from Square (1, 1) and reach (H, W) by repeatedly moving right or down to an adjacent empty square.

Find the number of Taro's paths from Square (1, 1) to (H, W).
As the answer can be extremely large, find the count modulo 10^9 + 7.

Constraints

H and W are integers.

2 \leq H, W \leq 1000

a_{i, j} is . or #.

Squares (1, 1) and (H, W) are empty squares.

Input

Input is given from Standard Input in the following format:

H W
a_{1, 1}\ldotsa_{1, W}
:
a_{H, 1}\ldotsa_{H, W}

Output

Print the number of Taro's paths from Square (1, 1) to (H, W), modulo 10^9 + 7.

Sample Input 1

3 4
...#
.#..
....

Sample Output 1

3

There are three paths as follows:

Sample Input 2

5 2
..
#.
..
.#
..

Sample Output 2

0

There may be no paths.

Sample Input 3

5 5
..#..
.....
#...#
.....
..#..

Sample Output 3

24

Sample Input 4

20 20
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................

Sample Output 4

345263555

Be sure to print the count modulo 10^9 + 7.

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on 2019/3/7
Update on 2019/3/
Solved on 2019/3/  
@author: shinjisu
"""


# Educational Dynamic Programming
# import math
#import numpy as np
#import sys
#sys.setrecursionlimit(10**6)


def getInt(): return int(input())


def getIntList(): return [int(x) for x in input().split()]
#def getIntList(): return np.array(input().split(), dtype=np.longlong)


# def zeros(n): return [0]*n
#def zeros(n): return np.zeros(n, dtype=np.longlong)


# def getIntLines(n): return [int(input()) for i in range(n)]
"""
def getIntLines(n):
    data = zeros(n)
    for i in range(n):
        data[i] = getInt()
    return data


def getIntMat(n, m):  # n行に渡って、1行にm個の整数
    mat = zeros((n, m))
    #dmp(mat)
    for i in range(n):
        mat[i] = getIntList()
    return mat


# def zeros2(n, m): return [zeros(m)]*n # obsoleted zeros((n, m))で代替
"""

ALPHABET = [chr(i+ord('a')) for i in range(26)]
DIGIT = [chr(i+ord('0')) for i in range(10)]
N1097 = 10**9 + 7
INF = 10**18


def dmp(x, cmt=''):
    global debug
    if debug:
        if cmt != '':
            print(cmt, ':  ', end='')
        print(x)
    return x


def prob_H_v1():  # Grid 1    AC 10  TLE 6
    H, W = getIntList()
    dmp((H, W), 'H, W')
    a = []
    for i in range(H):
        a.append(input())
    dmp(a)
    WALL = '#'
    BLANK = '.'
    dp = zeros((H+1, W+1))
    dp[1, 1] = 1
    dmp(dp, 'dp initial')
    for i in range(H):
        for j in range(W):
            if a[i][j] == BLANK and (i > 0 or j > 0):
                dp[i+1, j+1] = (dp[i, j+1] + dp[i+1, j]) % N1097

    dmp(dp, 'dp')
    return dp[H, W]


def prob_H_v2():  # Grid 1  AC 11  TLE 5
    H, W = getIntList()
    dmp((H, W), 'H, W')
    a = []
    for i in range(H):
        a.append(input())
    dmp(a)
    WALL = '#'
    BLANK = '.'
    dp = zeros((H+1, W+1))
    dp[1, 1] = 1
    dmp(dp, 'dp initial')
    for i in range(1, H):
        if a[i][0] == BLANK:
            dp[i+1, 1] = dp[i, 1]
    for j in range(1, W):
        if a[0][j] == BLANK:
            dp[1, j+1] = dp[1, j]
    for i in range(1, H):
        for j in range(1, W):
            if a[i][j] == BLANK:
                dp[i+1, j+1] = (dp[i, j+1] + dp[i+1, j]) % N1097

    dmp(dp, 'dp')
    return dp[H, W]


def prob_H():  # Grid 1  AC 11  TLE 5
    H, W = getIntList()
    dmp((H, W), 'H, W')
    a = []
    for i in range(H):
        a.append(input())
    dmp(a)
    WALL = '#'
    BLANK = '.'
    dp = [[0]*(W+1)]*(H+1)
    dp[1][1] = 1
    dmp(dp, 'dp initial')
    for i in range(1, H):
        if a[i][0] == BLANK:
            dp[i+1][1] = dp[i][1]
    for j in range(1, W):
        if a[0][j] == BLANK:
            dp[1][j+1] = dp[1][j]
    for i in range(1, H):
        for j in range(1, W):
            if a[i][j] == BLANK:
                dp[i+1][j+1] = (dp[i][j+1] + dp[i+1][j]) % N1097

    dmp(dp, 'dp')
    return dp[H][W]


debug = False  # True False
ans = prob_H()
print(ans)
#for row in ans:
#    print(row)