#include "bits/stdc++.h"
using namespace std;
using ll = long long;
using Vi = vector<int>;
using Pii = pair<int,int>;
#define pb push_back
#define mp make_pair
#define x first
#define y second
#define rep(i,b,e) for (int i=(b); i < (e); i++)
#define each(a,x) for(auto& a : (x))
#define all(x) (x).begin(), (x).end()
#define sz(x) int((x).size())
#define prev prev_

Vi prev, cur;
int n, m;
vector<string> tbl;
ll ans;

void solve() {
	fill(all(cur), 1);

	rep(i, 1, sz(tbl)) {
		swap(cur, prev);
		cur[0] = 1;
		int d = 1;

		rep(j, 1, sz(tbl[i])) {
			if (tbl[i][j-1] == tbl[i][j]) d++;
			else d = 1;
			cur[j] = min(d, prev[j]+1);
			if (tbl[i][j] != tbl[i-1][j]) cur[j] = 1;

			if (cur[j] > 1) {
				ans += cur[j]-1;
			}
		}
	}
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(18);

	cin >> n >> m;
	tbl.resize(n);
	each(r, tbl) cin >> r;

	prev.resize(max(n, m));
	cur.resize(max(n, m));

	solve();
	reverse(all(tbl));
	solve();
	each(s, tbl) reverse(all(s));
	solve();
	reverse(all(tbl));
	solve();

	cout << ans << endl;
	return 0;
}