#include <stdio.h>
#include <vector>
#include <string.h>
#include <algorithm>
#include <string>
#include <map>

using namespace std;

#define REP(A,B) for(int (A)=0;(A)<(B);(A)++)

char SRC[1111][1111];
char SRC2[1111][1111];
int P[1111][1111];
int M[1111][1111];
int n,m;
long long total = 0;

void go() {
	memset(M, 0, sizeof(M));
	memset(P, 0, sizeof(P));
	/*
	REP(i, n) {
		REP(j, m) {
			printf("%c", SRC[i][j]);
		}
		printf("\n");
	}
	printf("\n");*/
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++)
			P[i][j] = (j == 0 || SRC[i][j] != SRC[i][j-1]) ? 1 : P[i][j-1]+1;
	}
	for(int i = n-1; i >= 0; i--) {
		for(int j = 0; j < m; j++) {
			if(i < n-1 && SRC[i][j] == SRC[i+1][j]) {
				M[i][j] = min(M[i+1][j]+1, P[i][j]);
			} else {
				M[i][j] = 1;
			}
			total += M[i][j]-1;
		}
	}
}
void transpose() {
	REP(i, n) REP(j, m) SRC2[j][i] = SRC[i][j];
	REP(i, m) REP(j, n) SRC[i][j] = SRC2[m-i-1][j];
	swap(n, m);
}
int main()
{
	scanf("%d%d", &n, &m);
	REP(i, n) scanf("%s", SRC[i]);
	go();
	transpose();
	go();
	transpose();
	go();
	transpose();
	go();
	printf("%lld\n", total);
	return 0;
}