#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <iostream>
#include <cassert>
#include <cstring>

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)

#define TRACE(x) cerr << #x << " = " << x << endl
#define _ << " _ " <<

#define pb push_back
#define X first
#define Y second

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

int n, m;
vector<string> mat;

int num[1005][1005];

ll calc(){
  ll sol = 0;
  REP(i,n) num[i][m-1] = 0;
  REP(j,m) num[n-1][j] = 0;
  for (int i = n-2; i >= 0; --i)
    for (int j = m-2; j >= 0; --j){
      if (mat[i][j] == mat[i][j+1] && mat[i][j] == mat[i+1][j])
	num[i][j] = 1 + min(num[i][j+1], num[i+1][j]);
      else num[i][j] = 0;
      sol += num[i][j];
    } return sol;
}

void rotate(){
  vector<string> nmat;
  REP(j,m) nmat.pb(string(n, ' '));
  REP(i,n) REP(j,m) nmat[m-1-j][i] = mat[i][j];
  mat = nmat;
  swap(n, m);
}

int main(){
  ios_base::sync_with_stdio(false);

  cin >> n >> m;
  REP(i,n){string s; cin >> s; mat.pb(s);}

  ll sol = 0;
  REP(i,4){
    sol += calc();
    rotate();
  } cout << sol << endl;
  
  return 0;
}