#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;

template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;

#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
#define rep(i, m, n) for(ll i = (ll)(m); i < (ll)(n); ++i)
#define rep2(i, m, n) for(ll i = (ll)(n)-1; i >= (ll)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)

constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
// constexpr long long MOD = 998244353LL;
static const ld pi = 3.141592653589793L;

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

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;
}

//グラフ関連
struct Edge {
    int to, rev;
    ll cap;
    Edge(int _to, int _rev, ll _cap) : to(_to), rev(_rev), cap(_cap) {}
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

void add_edge(Graph &G, int from, int to, ll cap, bool revFlag, ll revCap) {
    G[from].push_back(Edge(to, (int)G[to].size(), cap));
    if(revFlag)
        G[to].push_back(Edge(from, (int)G[from].size() - 1, revCap));
}

template <int mod>
struct ModInt {
    int x;

    ModInt() : x(0) {}

    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    ModInt &operator+=(const ModInt &p) {
        if((x += p.x) >= mod)
            x -= mod;
        return *this;
    }

    ModInt &operator-=(const ModInt &p) {
        if((x += mod - p.x) >= mod)
            x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p) {
        x = (int)(1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p) {
        *this *= p.inverse();
        return *this;
    }

    ModInt operator-() const { return ModInt(-x); }

    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

    bool operator==(const ModInt &p) const { return x == p.x; }

    bool operator!=(const ModInt &p) const { return x != p.x; }

    ModInt inverse() const {
        int a = x, b = mod, u = 1, v = 0, t;
        while(b > 0) {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const {
        ModInt ret(1), mul(x);
        while(n > 0) {
            if(n & 1)
                ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    friend ostream &operator<<(ostream &os, const ModInt &p) {
        return os << p.x;
    }

    friend istream &operator>>(istream &is, ModInt &a) {
        int64_t t;
        is >> t;
        a = ModInt<mod>(t);
        return (is);
    }

    static int get_mod() { return mod; }
};

using mint = ModInt<MOD>;

void solve() {
    ll h, w;
    cin >> h >> w;
    vec<string> s(h);
    REP(i, h) {
        cin >> s[i];
    }
    if(s[0][0] != s[h - 1][w - 1]) {
        cout << 0 << en;
        return;
    }

    vector dp(h + w, vector(h + w, vector(h + w, mint(0))));
    dp[0][h][w] = 1; // s[0][0]とs[h-1][w-1]にいる状態
    int d = (h + w - 1 + 1) / 2 - 1;
    ll dx[2] = {1, 0};
    ll dy[2] = {0, 1};
    mint ans = 0;
    REP(i, d) {
        // cout << "d:" << i << en;
        REP(j, h + w) {
            REP(k, h + w) {
                if(dp[i][j][k].x == 0)
                    continue;
                int x1 = (i + j - h) / 2;
                int y1 = (i - j + h) / 2;
                int x2 = (h + w - 1 - i + k - h) / 2;
                int y2 = (h + w - 1 - i - k + h) / 2;
                // cout << x1 << " " << y1 << " " << x2 << " " << y2 << en;
                REP(v1, 2) {
                    ll nx1 = x1 + dx[v1];
                    ll ny1 = y1 + dy[v1];
                    if(nx1 < 0 or nx1 >= w or ny1 < 0 or ny1 >= h)
                        continue;
                    REP(v2, 2) {
                        ll nx2 = x2 - dx[v2];
                        ll ny2 = y2 - dy[v2];
                        if(nx2 < 0 or nx2 >= w or ny2 < 0 or ny2 >= h)
                            continue;
                        if(s[ny1][nx1] != s[ny2][nx2])
                            continue;
                        ll nj = nx1 - ny1 + h;
                        ll nk = nx2 - ny2 + h;
                        // cout << nx1 << " " << ny1 << " " << nx2 << " " << ny2 << en;

                        if(i + 1 == d) {
                            if((h + w - 1) % 2) {
                                if(nx1 == nx2 and ny1 == ny2)
                                    ans += dp[i][j][k];
                            } else {
                                if(abs(nx2 - nx1) + abs(ny2 - ny1) <= 1)
                                    ans += dp[i][j][k];
                            }
                            continue;
                        }
                        dp[i + 1][nj][nk] += dp[i][j][k];
                    }
                }
            }
        }
        // REP(j, h + w) {
        //     REP(k, h + w) {
        //         cout << dp[i][j][k] << " ";
        //     }
        //     cout << en;
        // }
    }
    // REP(i, d) {
    //     cout << "d:" << i << en;
    //     REP(j, h + w) {
    //         REP(k, h + w) {
    //             cout << dp[i][j][k] << " ";
    //         }
    //         cout << en;
    //     }
    //     cout << en;
    // }
    cout << ans << en;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    // cout << fixed << setprecision(10);

    // ll t;
    // cin >> t;
    // REP(i, t - 1) {
    //     solve();
    // }

    solve();

    return 0;
}