#include <bits/stdc++.h>
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
using namespace std;
namespace ywy {
char v[300][300];
long long dk1[300], dk2[300];
int dp[600];
typedef struct _p {
  long long h1, h2;
  _p() {
    h1 = 2333;
    h2 = 6663;
  }
  friend bool operator==(const _p &a, const _p &b) {
    return (a.h1 == b.h1 && a.h2 == b.h2);
  }
  friend bool operator!=(const _p &a, const _p &b) {
    return ((a.h1 != b.h1) || (a.h2 != b.h2));
  }
  inline void insert(char x) {
    h1 += dk1[x - 'a' + 1];
    h1 %= 998244353;
    h2 += dk2[x - 'a' + 1];
    h2 %= 1000000007;
  }
} pair;
pair str[600], real[600];
int s[300];
inline int solve(int n) {
  int ptr = 0, mid = 1, ans = 0;
  for (register int i = 2; i <= n; i++) {
    if (mid + ptr < i)
      mid = i, ptr = 0, dp[i] = 0;
    else
      dp[i] = min(mid + ptr - i, dp[mid * 2 - i]);
    while (dp[i] < min(n - i, i - 1) &&
           str[i + dp[i] + 1] == str[i - dp[i] - 1])
      dp[i]++;
    if (i + dp[i] >= mid + ptr) mid = i, ptr = dp[i];
    if ((i & 1) == 0 && (s[i >> 1] != (s[i >> 1] & -s[i >> 1]))) continue;
    ans += (dp[i] + 1) / 2;
  }
  return (ans);
}
void ywymain() {
  int n, m;
  cin >> n >> m;
  for (register int i = 1; i <= n; i++) {
    for (register int j = 1; j <= m; j++) cin >> v[i][j];
  }
  dk1[0] = dk2[0] = 1;
  for (register int i = 1; i <= 26; i++) {
    dk1[i] = (dk1[i - 1] * 233) % 998244353;
    dk2[i] = (dk2[i - 1] * 233) % 1000000007;
  }
  int ans = 0;
  for (register int l = 1; l <= m; l++) {
    memset(s, 0, sizeof(s));
    for (register int i = 1; i <= n * 2 + 1; i++) str[i] = real[i] = _p();
    for (register int r = l; r <= m; r++) {
      for (register int i = 1; i <= n; i++) {
        s[i] ^= (1 << (v[i][r] - 1));
        real[i].insert(v[i][r]);
        if (s[i] != (s[i] & -s[i])) {
          str[i * 2].h1 = i + 19260817;
          str[i * 2].h2 = 19260817 - i;
        } else
          str[i * 2] = real[i];
      }
      ans += solve(n * 2 + 1);
    }
  }
  cout << ans << endl;
}
}  // namespace ywy
int main() {
  ywy::ywymain();
  return (0);
}
