#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

using ll = long long;

void forgat(vector<string>& tomb, vector<string>& tomb2)
{
    int N = tomb.size();
    int M = tomb[0].size();
    for(int i = 0; i < N; i++)
    {
        for(int j = 0 ; j < M; j++)
        {
            tomb2[j][N - i - 1] = tomb[i][j];
        }
    }
    swap(tomb, tomb2);
}

ll megold(vector<string>& tomb)
{
    int N = tomb.size();
    int M = tomb[0].size();
    ll er = 0;
    vector<vector<int>> szamok(N, vector<int>(M, 0));
    for(int i = 1; i < N; i++)
    {
        for(int j = 0; j < M - 1; j++)
        {
            if(tomb[i-1][j] == tomb[i][j] && tomb[i - 1][j + 1] == tomb[i][j])
            {
                er += (szamok[i][j] = min(szamok[i-1][j], szamok[i-1][j + 1]) + 1);
            }
        }
    }
    return er;
}

int main()
{
    ios::sync_with_stdio(false);
    int N, M;
    cin >> N >> M;
    vector<string> tomb(N);
    for(string& s : tomb)
    {
        cin >> s;
    }
    vector<string> tomb2(M, string(N, '\0'));
    ll er = 0;
    for(int i = 0; i < 4; i++)
    {
        er += megold(tomb);
        forgat(tomb, tomb2);
    }
    cout << er << "\n";
}