import sys
input = sys.stdin.readline
from collections import *

H, W = map(int, input().split())
S = [input()[:-1] for _ in range(H)]

if S[0][0]!=S[-1][-1]:
    exit(print(0))

ind = [[-1]*W for _ in range(H)]
d = defaultdict(list)

for i in range(H):
    for j in range(W):
        ind[i][j] = len(d[H-1-i+W-1-j])
        d[H-1-i+W-1-j].append((i, j))

dp = [[[0]*210 for _ in range(W)] for _ in range(H)]
dp[0][0][0] = 1
MOD = 10**9+7

for i in range(H):
    for j in range(W):
        for k in range(210):
            if k>=len(d[i+j]):
                continue
            
            i2, j2 = d[i+j][k]
            
            if i>=i2 and j>=j2:
                continue
            
            for ni, nj in [(i+1, j), (i, j+1)]:
                for ni2, nj2 in [(i2-1, j2), (i2, j2-1)]:
                    if not (0<=ni<H and 0<=nj<W and 0<=ni2<H and 0<=nj2<W):
                        continue
                    
                    if (ni, nj)==(ni2, nj2) or S[ni][nj]==S[ni2][nj2]:
                        dp[ni][nj][ind[ni2][nj2]] += dp[i][j][k]
                        dp[ni][nj][ind[ni2][nj2]] %= MOD

ans = 0

for i in range(H):
    for j in range(W):
        if 2*(i+j)==H+W-2:
            ans += dp[i][j][ind[i][j]]
            ans %= MOD
            
        for ni, nj in [(i+1, j), (i, j+1)]:
            if not (0<=ni<H and 0<=nj<W):
                continue
            
            if i+j==H-ni+W-nj-2 and i+j+H-ni+W-nj==H+W-1:
                ans += dp[i][j][ind[ni][nj]]
                ans %= MOD

print(ans)