#include <iostream>
#include <vector>
#include <string>
using namespace std;

typedef long long ll;

ll n, m;

ll dyn(vector<vector<char>>& w) {
	vector<vector<ll>> d(n);
	ll result = 0;
	for(ll i = 0; i < n; i++) {
		d[i].resize(m);
		for(ll j = 0; j < m; j++) {
			if(i == 0)
				d[i][j] = 1;
			else {
				char tl = 0;
				if(j > 0)
					tl = w[i - 1][j - 1];
				if(tl == w[i][j] && tl == w[i - 1][j])
					d[i][j] = min(d[i - 1][j], d[i - 1][j - 1]) + 1;
				else
					d[i][j] = 1;
			}
			result += d[i][j] - 1;
		}
	}
	return result;
}

int main() {
	cin >> n >> m;
	vector<vector<char>> world(n);
	for(ll i = 0; i < n; i++) {
		string s;
		cin >> s;
		for(char c : s)
			world[i].push_back(c);
	}
	ll result = 0;
	for(ll i = 0; i < 4; i++) {
		result += dyn(world);
		vector<vector<char>> nworld(m);
		for(ll x = 0; x < n; x++) {
			for(ll y = 0; y < m; y++)
				nworld[y].push_back(world[x][m - 1 - y]);
		}
		world = nworld;
		swap(n, m);
	}
	cout << result << endl;
}