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

mod=10**9+7

H,W=map(int,input().split())
MAP=[input().strip() for i in range(H)]

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

DP=dict()
DP[0,0,H-1,W-1]=1

for i in range((H+W-2)//2):
    NDP=defaultdict(int)

    for x,y,z,w in DP:
        if 0<=x<H and 0<=z<H and 0<=y+1<W and 0<=w-1<W and MAP[x][y+1]==MAP[z][w-1]:
            NDP[x,y+1,z,w-1]+=DP[x,y,z,w]
            NDP[x,y+1,z,w-1]%=mod

        if 0<=x<H and 0<=z-1<H and 0<=y+1<W and 0<=w<W and MAP[x][y+1]==MAP[z-1][w]:
            NDP[x,y+1,z-1,w]+=DP[x,y,z,w]
            NDP[x,y+1,z-1,w]%=mod

        if 0<=x+1<H and 0<=z<H and 0<=y<W and 0<=w-1<W and MAP[x+1][y]==MAP[z][w-1]:
            NDP[x+1,y,z,w-1]+=DP[x,y,z,w]
            NDP[x+1,y,z,w-1]%=mod

        if 0<=x+1<H and 0<=z-1<H and 0<=y<W and 0<=w<W and MAP[x+1][y]==MAP[z-1][w]:
            NDP[x+1,y,z-1,w]+=DP[x,y,z,w]
            NDP[x+1,y,z-1,w]%=mod
    DP=NDP

if (H+W)%2==0:
    ANS=0
    for x,y,z,w in DP:
        if x==z and y==w:
            ANS+=DP[x,y,z,w]
            ANS%=mod
    print(ANS)
    
else:
    ANS=0
    for x,y,z,w in DP:
        if x==z and y+1==w:
            ANS+=DP[x,y,z,w]
            ANS%=mod
        if x+1==z and y==w:
            ANS+=DP[x,y,z,w]
            ANS%=mod
            
    print(ANS)