#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>

using namespace std;

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

int n, m;

vector<vector<int>> flip1(const vector<vector<int>> &a) {
  vector<vector<int>> b(n, vector<int>(m));
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      b[i][m - j - 1] = a[i][j];
    }
  }
  return b;
}

vector<vector<int>> flip2(const vector<vector<int>> &a) {
  vector<vector<int>> b(n, vector<int>(m));
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      b[n - i - 1][j] = a[i][j];
    }
  }
  return b;
}

llint solve(const vector<vector<int>> &a) {
  vector<vector<int>> most_at(n, vector<int>(m));
  for (int i = n - 1; i >= 0; --i) {
    std::vector<int> at(m);
    at[m - 1] = 1;
    for (int j = m - 2; j >= 0; --j) {
      if (a[i][j] == a[i][j + 1]) {
        at[j] = at[j + 1] + 1;
      } else {
        at[j] = 1;
      }
    }
    for (int j = 0; j < m; ++j) {
      if (i == n - 1 || a[i][j] != a[i + 1][j]) {
        most_at[i][j] = 1;
      } else {
        if (at[j] > most_at[i + 1][j]) {
          most_at[i][j] = most_at[i + 1][j] + 1;
        } else {
          most_at[i][j] = at[j];
        }
      }
    }
  }
  llint ans = 0;
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j)
      ans += most_at[i][j] - 1;
  return ans;
}

int main(void) {
  scanf("%d%d", &n, &m);
  vector<vector<int>> a;
  for (int i = 0; i < n; ++i) {
    char s[1024];
    scanf("%s", s);
    a.push_back(std::vector<int>());
    for (int j = 0; j < m; ++j) {
      a[i].push_back(s[j]);
    }
  }

  printf("%lld\n", solve(a) + solve(flip1(a)) +
      solve(flip2(a)) + solve(flip1(flip2(a))));
  return 0;
}