#include "bits/stdc++.h"
using namespace std;
const int N = 65000;
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,k;
cin >> n >> k;
string a[n];
for (int i = 0;i < n;i++){
cin >> a[i];
sort(a[i].begin(),a[i].end());
}
int p = 0;
for (int mask = 0;mask < (1 << n);mask++){
int h = __builtin_popcount(mask);
if (h < 2)
continue;
int l = h*(h-1)/2;
if (l < k)
continue;
map <string,int> mp;
for (int i = 0;i < n;i++){
if (mask >> i & 1)
mp[a[i]]++;
}
int cnt = 0;
for (auto &[s,c] : mp){
cnt += c*(c-1)/2;
if (cnt > k)
break;
}
if (cnt == k)
p++;
}
cout << p << "\n";
}
