#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
//#define int ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef RUS_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifdef RUS_HOME
    freopen("input", "r", stdin);
    //freopen("output.txt", "w", stdout);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef RUS_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

const int MOD=1e9+7,N=302,M=4e5+100,oo=1e9;

int n,m;

int dp[N][N],fp[N][N],f[N];

void smain() {

    cin>>n>>m;
    vector<string>s(n+1);
    for(int i=1;i<=n;i++){
        cin>>s[i];
    }
    for(int i=0;i<m;i++){
        for(int j=2;j<=n;j++){
            if(s[j][i]!=s[j-1][i])
                f[i]=1;
        }
    }

    ll ans=0;
    for(int col=1;col<m;col++){
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                fp[i][j]=dp[i][j]=0;
            }
        }
        string s1="#",s2="#";
        for(int j=1;j<=n;j++){
            s1+=s[j][col-1];
            s2+=s[j][col];
        }
        if(s1==s2&&!f[col]){
            for(int i=1;i<=n;i++){
                for(int j=1;j<=n;j++){
                    fp[i][j]=min(i,j);
                }
            }
        }else
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                if(s1[i]==s2[j]){
                    int diff=j-i;
                    for(int h=n;h>=i;h--){
                        int g=h+diff;
                        if(g>n)
                            continue;
                        if(g<1)
                            break;
                        fp[h][g]++;
                    }
                }
            }
        }
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                dp[i][j]=min(dp[i-1][j],dp[i][j-1])+fp[i][j];
            }
        }
        ans+=dp[n][n];
    }
    cout<<ans;

}



Measured memory_bytes: 4444