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

#define st first
#define nd second
typedef pair < int, int > PII;

const int N = 1e3 + 7, M = 94 + 7;
int A[N][N], Pref1[N][N][M], Pref2[N][N][M];
int n, m;

int main ()
{
	scanf("%d %d", &n, &m);

	for (int i = 1; i <= n; ++i)
		for (int j = 1; j <= m; ++j)
		{
			char c;
			scanf(" %c", &c);

			int letter = (int)(c - (char)33);
			A[i][j] = letter;
		}

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            int letter = A[i][j];
            for (int k = 0; k < M; ++k)
                Pref1[i][j][k] = Pref1[i - 1][j + 1][k],
                Pref2[i][j][k] = Pref2[i - 1][j - 1][k];

            ++Pref1[i][j][letter];
            ++Pref2[i][j][letter];
        }

    int result = 0;

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            int letter = A[i][j], d = 2;
            PII start = {i, j + 1}, finish = {i + 1, j};

            while (start.nd <= m && finish.st <= n)
            {
                if (Pref1[finish.st][finish.nd][letter] - Pref1[start.st - 1][start.nd + 1][letter] == d)
                    ++result;
                else
                    break;

                ++d;
                ++finish.st;
                ++start.nd;
            }
        }

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            int letter = A[i][j], d = 2;
            PII start = {i - 1, j}, finish = {i, j - 1};

            while (start.st > 0 && finish.nd > 0)
            {
                if (Pref1[finish.st][finish.nd][letter] - Pref1[start.st - 1][start.nd + 1][letter] == d)
                    ++result;
                else
                    break;

                ++d;
                --finish.nd;
                --start.st;
            }
        }

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            int letter = A[i][j], d = 2;
            PII start = {i, j - 1}, finish = {i + 1, j};

            while (start.nd > 0 && finish.st <= n)
            {
                if (Pref2[finish.st][finish.nd][letter] - Pref2[start.st - 1][start.nd - 1][letter] == d)
                    ++result;
                else
                    break;

                ++d;
                ++finish.st;
                --start.nd;
            }
        }

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            int letter = A[i][j], d = 2;
            PII start = {i - 1, j}, finish = {i, j + 1};

            while (start.st > 0 && finish.nd <= m)
            {
                if (Pref2[finish.st][finish.nd][letter] - Pref2[start.st - 1][start.nd - 1][letter] == d)
                    ++result;
                else
                    break;

                ++d;
                ++finish.nd;
                --start.st;
            }
        }

    printf("%d", result);

	return 0;
}