#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
#define FOR(i,l,r) for(ll i=l;i<r;i++)
#define REP(i,n) FOR(i,0,n)
#define RFOR(i,l,r) for(ll i=r-1;i>=l;i--)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(x) x.begin(),x.end()
#define PA pair<ll,ll>
#define F first
#define S second
#define BS(A,x) binary_search(ALL(A),x)
#define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin())
#define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin())
#define COU(A,x) (UB(A,x)-LB(A,x))
//#include<boost/multiprecision/cpp_int.hpp>
//namespace mp=boost::multiprecision;
//using Bint=mp::cpp_int;
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
template<class T>void print(vector<T>A){REP(i,A.size()){if(i)cout<<" ";cout<<A[i];}cout<<endl;}
ld dist(ld x1,ld y1,ld x2,ld y2){return sqrtl((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));}
using mint=modint1000000007;
//using mint=modint998244353;
const ll mod=1000000007;
//const ll mod=998244353;
//using mint=modint;
int main(){
  ll H,W;cin>>H>>W;
  vector<string>S(H);
  REP(i,H)cin>>S[i];
  if(H+W==2){cout<<1<<endl;return 0;}
  vector<vector<vector<mint>>>DP(H,vector<vector<mint>>(W,vector<mint>(H)));
  if(S[0][0]==S[H-1][W-1])DP[0][0][H-1]=1;
  FOR(t,1,(H+W)/2)REP(i,H){
    ll j=t-i;
    if(j<0||j>=W)continue;
    REP(k,H){
      ll l=H+W-2-t-k;
      if(l<0||l>=W||S[i][j]!=S[k][l])continue;
      //DP[i][j][k]
      if(i&&k<H-1&&S[i-1][j]==S[k+1][l])DP[i][j][k]+=DP[i-1][j][k+1];
      if(i&&l<W-1&&S[i-1][j]==S[k][l+1])DP[i][j][k]+=DP[i-1][j][k];
      if(j&&k<H-1&&S[i][j-1]==S[k+1][l])DP[i][j][k]+=DP[i][j-1][k+1];
      if(j&&l<W-1&&S[i][j-1]==S[k][l+1])DP[i][j][k]+=DP[i][j-1][k];
    }
  }
  mint ans=0;
  REP(i,H)REP(j,W)if(i+j==(H+W-2)/2){
    ans+=DP[i][j][i];
    if(i<H-1&&(H+W)%2)ans+=DP[i][j][i+1];
  }
  cout<<ans.val()<<endl;
  return 0;
}