"""

https://yukicoder.me/problems/no/1916

dpかな
200*200*200?

"""

import sys
from sys import stdin

H,W = map(int,stdin.readline().split())
if H == W == 1:
    print (1)
    sys.exit()

S = [list(stdin.readline()[:-1]) for i in range(H) ]

mod = 10**9+7

q = {}

if S[0][0] == S[H-1][W-1]:

    q[(0,0,H-1,W-1)] = 1

ans = 0

while q:

    newq = {}

    for tup in q:

        x1,y1,x2,y2 = tup
        cnt = q[tup]

        for newx1,newy1 in ( (x1+1,y1) , (x1,y1+1) ):
            for newx2,newy2 in ( (x2-1,y2) , (x2,y2-1) ):

                fl = (0<=newx1<H and 0<=newy1<W and 0<=newx2<H and 0<=newy2<W)
                if fl and newx1<=newx2 and newy1<=newy2 and S[newx1][newy1] == S[newx2][newy2]:
                    newtup = (newx1,newy1,newx2,newy2)

                    diff = abs(newx2-newx1) + abs(newy2-newy1)
                    if diff <= 1:
                        ans += cnt
                        ans %= mod
                    elif newtup not in newq:
                        newq[newtup] = cnt
                    else:
                        newq[newtup] += cnt
                        newq[newtup] %= mod

    q = newq
    #print (q)
print (ans % mod)