#include <bits/stdc++.h>
// solved by bekagg
#define int long long
#define ent '\n'
#define pb push_back
#define all(x) x.begin(),x.end()
#define PRaim_bek_abi ios_base::sync_with_stdio(0);cin.tie(0);
using namespace std;
const int N = 1e5+5;
const int MOD = 1e9+7;
int n , d , ans;
map<string , int>mp;
vector<char>v;
string s[N];
void arkanefury228(){
cin >> n >> d;
if (n <= 2000){
for (int i = 1; i <= n; i++){
cin >> s[i];
for (int j = 1; j < i; j++){
int sum = 0;
for (int k = 0; k < 4; k++){
if (s[i][k] != s[j][k]) sum++;
}
if (sum == d) ans++;
}
}
cout << ans;
return;
}
if (d == 0){
for (int i = 1; i <= n; i++){
cin >> s[i];
ans += mp[s[i]];
mp[s[i]]++;
}
cout << ans;
return;
}
}
signed main(){
PRaim_bek_abi
int t=1;
//cin>>t;
for (int respagold = 1; respagold <= t; respagold++) arkanefury228();
}
