#!/usr/bin/env PyPy3

from collections import Counter, defaultdict, deque
import itertools
import re
import math
from functools import reduce
import operator
import bisect
from heapq import *
import functools
mod=10 ** 9 + 7

import sys
input=sys.stdin.readline
h,w=map(int,input().split())
s=[input().rstrip() for _ in range(h)]
dp = [[[0] * h for _ in range(h)] for _ in range(h + w - 1)]
if s[0][0] == s[-1][-1]:
    dp[0][0][h-1] = 1
    ans = 0
    for i in range(1,(h+w-1) // 2 + 1):
        for sh in range(h):
            sw = i - sh
            if 0 <= sh < h and 0 <= sw < w:
                for gh in range(h):
                    gw = h + w - 2 - i - gh
                    if 0 <= gh < h and 0 <= gw < w:
                        if s[sh][gw] == s[gh][gw]:
                            tmp1 = 0
                            if sh > 0 and gh < h - 1:
                                tmp1 += dp[i-1][sh - 1][gh + 1]
                            if sh > 0 and gw < w - 1:
                                tmp1 += dp[i-1][sh-1][gh]
                                tmp1 %= mod
                            if sw > 0 and gh < h - 1:
                                tmp1 += dp[i-1][sh][gh + 1]
                                tmp1 %= mod
                            if sw > 0 and gw < w - 1:
                                tmp1 += dp[i-1][sh][gh]
                                tmp1 %= mod
                            if gh >= sh and gw >= sw and gh + gw - sh - sw <= 1:
                                ans += tmp1
                                ans %= mod
                            else:
                                dp[i][sh][gh] = tmp1
    print(ans)
    #print(dp)
else:
    print(0)