#include <bits/stdc++.h>
using namespace std;
// Typedef
typedef long double ld;
typedef long long int int64;
typedef unsigned long long int uint64;
typedef std::pair<int, int> PII;
typedef std::pair<int64, int64> PLL;
typedef std::vector<int> VI;
typedef std::vector<long long> VLL;
// Define For-loop
#define FOR(i, j, k, in) for (int i = (j); i < (k) ; i += (in))
#define FORW(i, j, k, in) for (int i = (j); i <= (k); i += (in))
#define RFOR(i, j, k, in) for (int i = (j); i >= (k); i -= (in))
// Define Data structure func
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.rbegin(), cont.rend()
#define sz(cont) int((cont).size())
#define pb push_back
#define mp make_pair
#define fi first
#define se second
// Define number
#define IINF 0x3f3f3f3f
#define LLINF 1000111000111000111LL
#define PI 3.1415926535897932384626433832795
// Other
#define lend '\n'
#define hardio(name) freopen(name".inp","r",stdin), freopen(name".out","w",stdout);
void FastIO() { std::ios_base::sync_with_stdio(false); std::cin.tie(NULL); cin.exceptions(cin.failbit); srand(time(NULL)); }
const int N = 5e5 + 6, base = 331, LG = (1 << 4) - 1;
const int MOD = 1e9 + 7, MOD2 = 1e9 + 9;
// ======================================================================
int n, d;
map<int, int> hsh;
int cnt[56] = {};
int64 val[6] = {};
string s[N] = {};
/*
abcd
=> 4: abcd = 1
=> 3: abc abd acd bcd = 4
=> 2: ab ac ad bc bd cb = 6
=> 1: a b c d = 4
======================
We can see the answer will be overlapping:
+ With 3 characters, there'll be 4C3 way to abstract [choose 4]
+ With 2 characters, there'll be 4C2 way to abstract [choose 4], 3C2 way to abstract [choose 3]
+ With 1 characters, there'll be 4C1 way to abstract [choose 4], 3C1 way to abstract [choose 3], 2C1 way to abstract [choose 2]
+ With 0 characters, 4C0 + 3C0 + 2C0 + 1C0
*/
int main(int argc, char* argv[]) { FastIO();
cin >> n >> d;
FORW(i, 1, n, 1) { cin >> s[i]; s[i] = '$' + s[i]; }
FORW(i, 1, LG, 1) cnt[i] = cnt[i >> 1] + (i & 1);
FORW(mask, 0, LG, 1) {
hsh.clear();
FORW(i, 1, n, 1) {
int sum = 0;
FORW(k, 1, 4, 1) sum = sum * base + ((mask >> (k - 1)) & 1 ? s[i][k] : 1);
val[cnt[mask]] += hsh[sum];
hsh[sum]++;
}
}
val[3] -= 4 * val[4];
val[2] -= 6 * val[4] + 3 * val[3];
val[1] -= 4 * val[4] + 3 * val[3] + 2 * val[2];
val[0] -= val[1] + val[2] + val[3] + val[4];
cout << val[4 - d] << '\n';
return 0; }
