#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={0,1,-1,0,1,1,-1,-1,0};
const ll dx[9]={1,0,0,-1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}


const int mod = MOD;
const int max_n = 200005;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
  bool operator==(const mint &p) const { return x == p.x; }
  bool operator!=(const mint &p) const { return x != p.x; }
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
using vm=vector<mint>;
using vvm=vector<vm>;
struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
}comb(max_n);
mint dp[210][210][210];
int main(){
    rep(i,210)rep(j,210)rep(k,210)dp[i][j][k]=0;
    ll h,w;cin >> h >> w;
    vector<string> g(h);rep(i,h)cin >> g[i];
    if(g[0][0]!=g[h-1][w-1]){
        cout << 0 << endl;return 0;
    }
    dp[0][0][h-1]=1;
    rep(i,(h+w-1)/2){
        rep(j,h){
            rep(k,h){
                if(dp[i][j][k]==0)continue;
                rep(s,2){
                    ll ndx=j+dx[s],ndy=i-j+dy[s];
                    if(ndx<0||ndy<0||ndx>=h||ndy>=w)continue;
                    rep(d,2){
                        ll nndx=k+dx[d+2],nndy=(h+w-2-i)-k+dy[d+2];
                        if(nndx<0||nndy<0||nndx>=h||nndy>=w)continue;
                        if(g[ndx][ndy]==g[nndx][nndy]){
                            dp[i+1][ndx][nndx]+=dp[i][j][k];
                        }
                    }
                }
            }
        }
    }
    mint ans=0;
    if((h+w-1)&1){
        rep(i,210){
            ans+=dp[(h+w-1)/2][i][i];
            //if(dp[(h+w-1)/2][i][i]!=0)cout << i << " " << dp[(h+w-1)/2][i][i] << endl;
        }
    }
    else{
        rep(i,210)rep(j,210)rep(k,210){
            ll x=j,y=i-x;
            ll xx=k,yy=h+w-2-i-xx;
            if(x<0||y<0||x>=h||y>=w)continue;
            if(xx<0||yy<0||xx>=h||yy>=w)continue;
            if((x==xx&&y+1==yy)||(y==yy&&x+1==xx))ans+=dp[i][j][k];
        }
    }
    cout << ans << endl;

}