import pypyjit
pypyjit.set_param("max_unroll_recursion=-1")
import sys
sys.setrecursionlimit(10**7)
from functools import cache
MOD = 10**9+7
H,W = list(map(int,input().split()))
S = [input() for _ in range(H)]

dy = [0,1]
dx = [1,0]
ddy = [0,-1]
ddx = [-1,0]
@cache
def f(y,x,yy):
    xx = (H-1 + W-1) - yy - x - y
    if(y+x == (H+W-2)//2):return int(abs(y - yy) + abs(x - xx) <= 1)
    ret = 0
    for i in range(2):
        next_y = y + dy[i]
        next_x = x + dx[i]
        if(next_y < 0 or H <= next_y):continue
        if(next_x < 0 or W <= next_x):continue
        for j in range(2):
            next_yy = yy + ddy[j]
            next_xx = xx + ddx[j]
            if(next_yy < 0 or H <= next_yy):continue
            if(next_xx < 0 or W <= next_xx):continue
            if(S[next_y][next_x] != S[next_yy][next_xx]):continue
            ret += f(next_y, next_x, next_yy)
            ret %= MOD

    return ret

print(f(0,0,H-1) if S[0][0] == S[-1][-1] else 0)