#include<bits/stdc++.h>
using namespace std;

#define PII pair<int, int>
#define VI vector<int>
#define VPII vector<PII>
#define LL long long
#define f first
#define s second
#define MP make_pair
#define PB push_back
#define LD long double
#define endl '\n'
#define ALL(c) (c).begin(), (c).end()
#define SIZ(c) (int)(c).size()
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, b, e) for (int i = (b); i <= (int)(e); i++)
#define FORD(i, b, e) for (int i = (b); i >= (int)(e); i--)
#define ll LL
#define mp MP
#define pb PB
#define st f
#define nd s
#define eb emplace_back
const int inf = 1e9 + 7;
const LL INF = 1e18L + 7;

#define sim template<class n
sim, class s> ostream & operator << (ostream &p, pair<n, s> x)
{return p << "<" << x.f << ", " << x.s << ">";}
sim> auto operator << (ostream &p, n y) ->
typename enable_if<!is_same<n, string>::value, decltype(y.begin(), p)>::type
{int o = 0; for (auto c : y) {if (o++) p << ", "; p << c;} return p << "}";}
void dor() {cerr << endl;}
sim, class...s> void dor(n p, s...y) {cerr << p << " "; dor(y...);}
sim, class s> void mini(n &p, s y) {if (p > y) p = y;}
sim, class s> void maxi(n &p, s y) {if (p < y) p = y;}

#ifdef DEB
#define debug(...) dor(__FUNCTION__, ":", __LINE__, ": ", __VA_ARGS__)
#else
#define debug(...)
#endif

#define I(x) #x " =", (x), " "
#define A(a, i) #a "[" #i " =", i, "] =", a[i], " "
const int MXN = 1003;
int in[MXN][MXN];
int t[MXN][MXN];
int dp[MXN][MXN];

LL res = 0;

void calc(int n, int m) // obliczam z t
	{
	if(0)
	FOR(i, 1, n)
		{
		FOR(j, 1, m)
			{
			cerr  << (char)t[i][j];
			}
		cerr << endl;
		}
	
	
	FORD(i, n, 1)	
		FORD(j, m, 1)
			{
		    if(t[i][j] != t[i][j+1] || t[i][j] != t[i+1][j] || i == n || j == m)
		    	{
		    	dp[i][j] = 0; continue;
		    	}
			dp[i][j] = min(dp[i+1][j], dp[i][j+1])+1;
	
			res += max(0, dp[i][j]);
			
//			debug(i, j, dp[i][j]);
			}	
	if(0)
	FOR(i, 1, n)
		{
		FOR(j, 1, m)
			{
			cerr  << dp[i][j];
			}
		cerr << endl;
		}
	}

int main()
{
	int n, m;
	scanf("%d%d", &n, &m);
	
	FOR(i, 1, n)
		{
		FOR(j, 1, m)
			{
			char ch;
			scanf(" %c", &ch);
			in[i][j] = ch;
			}
		}
	
	REP(uu, 4)
		{
		FOR(i, 1, n)
			{
			FOR(j, 1, m)
				{
				t[j][n-i+1] = in[i][j];
				}
			}
		swap(n, m);
		FOR(i, 1, n)
			{
			FOR(j, 1, m)
				{
				in[i][j] = t[i][j];
				}
			}
		
		calc(n, m);

		
		}
	cout << res << endl;
}