#include<bits/stdc++.h>

using namespace std;

#define N 500005

unordered_map<long long,int> mp;

long long all,buffer;

int main(){

    ios::sync_with_stdio(0);

    cin.tie(0);

    mp.clear();

    int m,n,t=0;

    cin>>m>>n;

    all=(1<<m)-1;

    for(int i=0;i<n;i++){

        buffer=0;

        string a;

        cin>>a;

        for(int j=0;j<(int)a.size();j++)

            if(a[j]>='a'){

                buffer |= 1LL<<(a[j]-'a'+26);

            }else

                buffer |= 1LL<<(a[j]-'A');

        t+=mp[buffer^all];

        mp[buffer]++;

    }

    cout<<t;

}