#include <bits/stdc++.h>

int n, m;

std::string tagid(std::string str) {
    std::string s = str + str, k, min;
    min = str;
    for(int i = 1; i < m; i++) {
        k = std::string(&s[i], &s[i+m]);
        if(min > k) min = k;
    }
    return min;
}

int main() {
    long long count = 0, cc = 1;
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::string cache;
    std::vector<std::string> ids;
    std::vector<int> veccount;
    std::unordered_map<std::string, int> map;
    std::cin >> n >> m;
    for(int i = 0; i < n; i++) {
        std::cin >> cache; 
        ids.push_back(tagid(cache));
    }

    map.insert({ids[0], 0});
    veccount.push_back(1);

    for(int i = 1; i < n; i++) {

        if (auto search = map.find(ids[i]); search != map.end()) {
            veccount[search->second]++;
        }
        else {
            map.insert({ids[i], cc});
            veccount.push_back(1);
            cc++;
        }
    }

    for(const auto x : veccount) {
        count += x*(x-1);
    }
    std::cout << count/2 << std::flush;
}