#include <algorithm>
#include <cmath>
#include <iostream>
#include <numeric>
#include <queue>
#include <vector>
using namespace std;
using ll = long long;
#define rep(i, j, n) for (int i = j; i < (n); ++i)
#define rrep(i, j, n) for (int i = (n)-1; j <= i; --i)
template <typename T>
std::ostream &operator<<(std::ostream &os, std::vector<T> &a) {
  for (size_t i = 0; i < a.size(); ++i) os << (i > 0 ? " " : "") << a[i];
  return os << '\n';
}
template <typename T>
std::istream &operator>>(std::istream &is, std::vector<T> &a) {
  for (T &x : a) { is >> x; }
  return is;
}
constexpr long long MOD = 1000000007;

ll dp[202][202][202];

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  cin >> s;
  // dp[a][b][c][d]
  // a+b = h+w-2 - (c+d)
  // len 1
  rep(a, 0, h) rep(b, 0, w) if ((a + b) * 2 == h + w - 2) dp[a][b][a] = 1;
  // len 2
  rep(a, 0, h) rep(b, 0, w) {
    if (a + 1 < h && (a + b) * 2 + 1 == h + w - 2 && s[a][b] == s[a + 1][b])
      dp[a][b][a + 1] = 1;
    if (b + 1 < w && (a + b) * 2 + 1 == h + w - 2 && s[a][b] == s[a][b + 1])
      dp[a][b][a] = 1;
  }
  // 長さ1or2の元　から　回文を両側に伸ばしていく
  // 対角線辺りから更新する
  rrep(m, 0, (h + w - 2) / 2 + 1) {
    // m=a+b=h+w-2-(c+d)
    rep(a, 0, h) {
      rep(c, 0, h) {
        int b = m - a, d = h + w - 2 - m - c;
        if (0 <= b && b < w && 0 <= d && d < w) {
          if (s[a][b] == s[c][d]) {
            (dp[a][b][c] += dp[a][b + 1][c - 1] + dp[a + 1][b][c - 1] +
                            dp[a + 1][b][c] + dp[a][b + 1][c]) %= MOD;
          }
        }
      }
    }
  }
  cout << dp[0][0][h - 1];

  return 0;
}