#include <bits/stdc++.h>

int n, m;
std::vector<int> a = {}, b = {};

std::string tagid2(std::string str) {
    a = {};
    int i = 0;
    char min = str[0];
    std::string str2 = str + str;

    for(auto x : str) {
        if (x < min) {
            a = {i};
            min = x;
        } else if (x == min) {
            a.push_back(i);
        }
        i++;
    }

    while(a.size() > 1) {
        b = {};
        min = str[a[0]+1];
        i = 0;
        for(auto x : a) {
            if (str[x+1] < min) {
                b = {i};
                min = str[x+1];
            } 
            else if (str[x+1] == min) {
                b.push_back(i);
            }
            i++;
        }
        a = b;
    }
    return std::string(&str2[a[0]], &str2[a[0]+m]);
}

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(tagid2(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;
}