#include <iostream>
#include <vector>

using namespace std;

int main()
{
    int n, m, i, j, k;
    cin >> n >> m;

	vector<int> count;
	vector<string> orderedcodes;
	string raw;

	for (i = 0; i < n; i++)
	{
		cin >> raw;
		
		raw += raw;

		vector<int> candidates;

		char min = 'z';

		for (j = 0; j < m; j++)
		{
			if (raw[j] < min)
			{
				min = raw[j];
			}
		}

		for (j = 0; j < m; j++)
		{
			if (raw[j] == min)
			{
				candidates.push_back(j);
			}
		}

		j = 1;
		while (candidates.size() > 1 && j < m)
		{
			min = 'z';
			for (k = 0; k < candidates.size(); k++)
			{
				if (raw[candidates[k]+j] < min)
				{
					min = raw[candidates[k] + j];
				}
			}

			for (k = 0; k < candidates.size(); k++)
			{
				if (raw[candidates[k]+j] > min)
				{
					candidates.erase(candidates.begin()+k);
					if (candidates.size() == 1)
					{
						break;
					}
				}
			}

			j++;
		}

		string ordered;

		for (j = 0; j < m; j++)
		{
			ordered.push_back(raw[candidates[0] + j]);
		}

		for (j = 0; j < orderedcodes.size(); j++)
		{
			if (ordered == orderedcodes[j])
			{
				count[j]++;
				break;
			}
		}

		if (j == orderedcodes.size())
		{
			orderedcodes.push_back(ordered);
			count.push_back(1);
		}
	}

	int out = 0;

	for (i = 0; i < count.size(); i++)
	{
		out += (count[i] * (count[i] - 1)) >> 1;
	}

	cout << out;
}