#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,abm,mmx,avx")
// #pragma comment(linker, "/stack:200000000"]

#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <bitset>
#include <stack>
#include <random>
#include <fstream>
#include <sstream>
#include <chrono>

#define fi first
#define se second
#define pb push_back
#define ll long long
#define ld long double
#define hm unordered_map
#define pii pair<int, int>
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define cinv(v) for (auto& x: v) cin >> x
#define fr(i, n) for (int i = 0; i < n; ++i)
#define fl(i, l, n) for (int i = l; i < n; ++i)

// #define int ll

using namespace std;

#ifdef __LOCAL
	#define dbg(x) cerr << #x << " : " << x << '\n'
	const int maxn = 20;
#else
	#define dbg(x)
	const int maxn = 2000 + 20;
#endif

//tg: @galebickosikasa

ostream& operator << (ostream& out, vector<int>& v) {
	for (auto& x: v) out << x << ' ';
	return out;
}

ostream& operator << (ostream& out, pii& v) {
	out << v.fi << ", " << v.se;
	return out;
}

istream& operator >> (istream& in, pii& a) {
	in >> a.fi >> a.se;
	return in;
}

const ll inf = (ll) 2e9;
const ld pi = asin (1) * 2;
const ld eps = 1e-8;
const ll mod = (ll)1e9 + 7;
const ll ns = 97;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

int dp1[maxn][maxn], dp2[maxn][maxn], dp3[maxn][maxn], dp4[maxn][maxn], dp5[maxn][maxn], dp6[maxn][maxn], dp7[maxn][maxn], dp8[maxn][maxn],
	dp[maxn][maxn], n, m;
char g[maxn][maxn];

void get1 (int i) {
	dp1[i][m - 1] = 1;
	for (int j = m - 2; j >= 0; --j) {
		if (g[i][j + 1] == g[i][j]) dp1[i][j] = dp1[i][j + 1] + 1;
		else dp1[i][j] = 1;
	}
}

void get2 (int i) {
	dp2[i][0] = 1;
	for (int j = 1; j < m; ++j) {
		if (g[i][j - 1] == g[i][j]) dp2[i][j] = dp2[i][j - 1] + 1;
		else dp2[i][j] = 1;
	}
}

void get3 (int j) {
	dp3[0][j] = 1;
	for (int i = 1; i < n; ++i) {
		if (g[i - 1][j] == g[i][j]) dp3[i][j] = dp3[i - 1][j] + 1;
		else dp3[i][j] = 1;
	}
}

void get4 (int j) {
	dp4[n - 1][j] = 1;
	for (int i = n - 2; i >= 0; --i) {
		if (g[i + 1][j] == g[i][j]) dp4[i][j] = dp4[i + 1][j] + 1;
		else dp4[i][j] = 1;
	}
}

void get5 (int i, int j) {
	dp5[i][j] = 1;
	fl (k, 1, inf) {
		if (i + k >= n || j - k < 0) break;
		if (g[i + k - 1][j - k + 1] == g[i + k][j - k]) dp5[i + k][j - k] = dp5[i + k - 1][j - k + 1] + 1;
		else dp5[i + k][j - k] = 1;
	}
}

void get6 (int i, int j) {
	dp6[i][j] = 1;
	fl (k, 1, inf) {
		if (i - k < 0 || j + k >= m) break;
		if (g[i - k + 1][j + k - 1] == g[i - k][j + k]) dp6[i - k][j + k] = dp6[i - k + 1][j + k - 1] + 1;
		else dp6[i - k][j + k] = 1;
	}
}

void get7 (int i, int j) {
	dp7[i][j] = 1;
	fl (k, 1, inf) {
		if (i + k >= n || j + k >= m) break;
		if (g[i + k - 1][j + k - 1] == g[i + k][j + k]) dp7[i + k][j + k] = dp7[i + k - 1][j + k - 1] + 1;
		else dp7[i + k][j + k] = 1;
	}
}

void get8 (int i, int j) {
	dp8[i][j] = 1;
	fl (k, 1, inf) {
		if (i - k < 0 || j - k < 0) break;
		if (g[i - k + 1][j - k + 1] == g[i - k][j - k]) dp8[i - k][j - k] = dp8[i - k + 1][j - k + 1] + 1;
		else dp8[i - k][j - k] = 1;
	}
}

void solve () {
	cin >> n >> m;
	fr (i, n) fr (j, m) cin >> g[i][j];
	fr (i, n) {
		get1 (i);
		get2 (i);
		get5 (i, m - 1);
		get6 (i, 0);
		get7 (i, 0);
		get8 (i, m - 1);
	}
	fr (j, m) {
		get3 (j);
		get4 (j);
		get5 (0, j);
		get6 (n - 1, j);
		get7 (0, j);
		get8 (n - 1, j);
	}
	// fr (i, n) fr (j, m) dbg (g[i][j]);
	fr (i, n) fr (j, m) dp[i][j] = min (min (min (dp1[i][j], dp2[i][j]), min (dp3[i][j], dp4[i][j])), min (min (dp5[i][j], dp6[i][j]), min (dp7[i][j], dp8[i][j])));
	int ans = 0;
	fr (i, n) fr (j, m) {
		dbg (i);
		dbg (j);
		dbg (dp[i][j]);
		dbg (dp1[i][j]);
		dbg (dp2[i][j]);
		dbg (dp3[i][j]);
		dbg (dp4[i][j]);
		dbg (dp5[i][j]);
		dbg (dp6[i][j]);
		dbg (dp7[i][j]);
		dbg (dp8[i][j]);
		ans += dp[i][j];
	}
	cout << ans << '\n';







}




signed main () {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int q = 1;
	// cin >> q;
	while (q--) solve ();







}