#include<atcoder/all>
#include<bits/stdc++.h>
using namespace atcoder;
using namespace std;
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fin(a) return pt(a)
using ll=long long;
using ld=long double;
using v1=vector<ll>;
using v2=vector<v1>;
using v3=vector<v2>;
using v4=vector<v3>;
using pll=pair<ll,ll>;
using mll=map<ll,ll>;
ll inf=1LL<<60;
ld pi=acos(-1);
ld eps=1e-10;
template<class T>using ascending_priority_queue=std::priority_queue<T,vector<T>,greater<T>>;
template<class T>using descending_priority_queue=std::priority_queue<T>;
template<class T>bool chmax(T&a,const T&b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,const T&b){if(b<a){a=b;return 1;}return 0;}
template<class V,class T>T max(vector<V>&vec,const T&id){T r=id;for(auto&v:vec)chmax(r,max(v,id));return r;}
template<class V,class T>T min(vector<V>&vec,const T&id){T r=id;for(auto&v:vec)chmin(r,min(v,id));return r;}
template<class T>pll mima(const T&a,const T&b){return {min(a,b),max(a,b)};}
template<class T>T sum(vector<T>&a){return accumulate(all(a),T(0));}
template<class T>T popcnt(T a){return __builtin_popcountll(a);}
istream&operator>>(istream&is,modint1000000007&x){unsigned int t;is>>t;x=t;return is;}
istream&operator>>(istream&is,modint998244353&x){unsigned int t;is>>t;x=t;return is;}
istream&operator>>(istream&is,modint&x){unsigned int t;is>>t;x=t;return is;}
ostream&operator<<(ostream&os,const modint1000000007&x){os<<x.val();return os;}
ostream&operator<<(ostream&os,const modint998244353&x){os<<x.val();return os;}
ostream&operator<<(ostream&os,const modint&x){os<<x.val();return os;}
template<class T1,class T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.first>>p.second;return is;}
template<class T1,class T2>ostream&operator<<(ostream&os,const pair<T1,T2>&p){os<<p.first<<" "<<p.second;return os;}
template<class T>istream&operator>>(istream&is,vector<T>&v){for(T&x:v)is>>x;return is;}
template<class T>ostream&operator<<(ostream&os,const vector<T>&v){for(int i=0;i<(int)v.size();i++){os<<v[i]<<(i+1==(int)v.size()?"":" ");}return os;}
template<class...A>int pt_rest(){cout<<'\n';return 0;}
template<class...A>int pt(){cout<<'\n';return 0;}
template<class T,class...A>int pt_rest(const T&first,const A&...rest){cout<<" "<<first;pt_rest(rest...);return 0;}
template<class T,class...A>int pt(const T&first,const A&...rest){cout<<first;pt_rest(rest...);return 0;}
template<class V,class H>void resize(vector<V>&vec,const H head){vec.resize(head);}
template<class V,class H,class...T>void resize(vector<V>&vec,const H&head,const T...tail){vec.resize(head);for(auto&v:vec)resize(v,tail...);}
template<class V,class T>void fill(V&x,const T&val){x=val;}
template<class V,class T>void fill(vector<V>&vec,const T&val){for(auto&v:vec)fill(v,val);}
template<class H>void vin(istream&is,const int idx,vector<H>&head){is>>head[idx];}
template<class H,class...T>void vin(istream&is,const int idx,vector<H>&head,T&...tail){vin(is>>head[idx],idx,tail...);}
template<class H,class...T>void vin(istream&is,vector<H>&head,T&...tail){for(int i=0;i<(int)head.size();i++)vin(is,i,head,tail...);}
template<class H,class...T>void vin(vector<H>&head,T&...tail){vin(cin,head,tail...);}
template<class H>void sin(istream&is,H&head){is>>head;}
template<class H,class...T>void sin(istream&is,H&head,T&...tail){sin(is>>head,tail...);}
template<class H,class...T>void sin(H&head,T&...tail){sin(cin,head,tail...);}
v1 divisor(ll n){mll m;for(ll i=1;i*i<=n;i++)if(n%i==0){m[i]++;m[n/i]++;}v1 v;for(auto[x,_]:m)v.emplace_back(x);return v;}
mll factor(ll n){mll m;for(ll i=2;i*i<=n;i++)while(n%i==0){m[i]++;n/=i;}if(n>1)m[n]++;return m;}
ll lsqrt(ll x){assert(x>=0);if(x<=1)return x;ll r=sqrt(x)-1;while((r+1)<=x/(r+1))r++;return r;};
using S=ll;
S op(S a,S b){return a+b;}
S e(){return 0;}



int main(void){
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  
  ll H,W;sin(H,W);
  vector<string>s(H);cin>>s;
  
  v1 dx={1,0},dy={0,1};
  v3 g;resize(g,H,W,2);
  for(ll i=0;i<H;i++){
    for(ll j=0;j<W;j++){
      if(i+j>=(H+W-1)/2)continue;
      
      ll T=H+W-2-i-j;
      for(ll k=0;k<=T;k++){
        ll l=T-k;
        if(k>=H or l>=W)continue;
        if(s[i][j]!=s[k][l])continue;
                
        for(ll p=0;p<2;p++){
          for(ll q=0;q<2;q++){
            ll ni=i+dx[p],nj=j+dy[p];
            ll pk=k-dx[q],pl=l-dy[q];
            
            if(ni>=H or nj>=W)continue;
            if(pk<0 or pl<0)continue;
            if(s[ni][nj]!=s[pk][pl])continue;
            
            if(pk==i or pl==j)g[i][j][p]=1;
            if(ni<=pk and nj<=pl){
              g[i][j][p]=1;
              g[pk][pl][q]=1;
            }
          }
        }
      }
    }
  }
  
  using mint=modint1000000007;
  vector<vector<mint>>dp;resize(dp,H,W);

  dp[0][0]=1;
  for(ll i=0;i<H;i++){
    for(ll j=0;j<W;j++){
      for(ll k=0;k<2;k++){
        ll ni=i+dx[k],nj=j+dy[k];
        if(ni>=H or nj>=W)continue;
        if(g[i][j][k]==0)continue;
        dp[ni][nj]+=dp[i][j];
      }
    }
  }
  pt(dp[H-1][W-1]);
}