#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int K = 4;
const int N = 5e4+1;
map<string, ll> mp[(1<<K)];
ll ans[6], n, d;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>n>>d;
for (int i=1; i<=n; ++i) {
string s; cin>>s;
for (int j=1; j<(1<<K); ++j) {
string tmp;
for (int x=0; x<K; ++x) {
if (j&(1<<x)) tmp+=s[x];
}
++mp[j][tmp];
}
}
for (int m=0; m<(1<<K); ++m) {
ll tmp=0;
for (auto u : mp[m]) tmp+=u.second*(u.second-1)/2;
ans[4-__builtin_popcount(m)]+=tmp;
}
if (d == 1) cout<<ans[1]-ans[0]<<"\n";
else if (d == 2) cout<<ans[2]-3*(ans[1]-ans[0])<<"\n";
else if (d == 3) cout<<ans[3]-2*ans[2]+3*(ans[1]-ans[0])<<"\n";
else if (d == 4) cout<<ans[4]-ans[3]+ans[2]-ans[1]+ans[0]<<"\n";
}
