#include <bits/stdc++.h>
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("Ofast,unroll-loops")
using namespace std;
int n,m,k,q;
vector<int>vis(2e6);
void solve(){
cin >> n >> k;
vector<string>v(n);
for(auto &to:v)cin >> to;
int res = 0;
if(n <= 2000){
for(int i = 0;i<n;i++){
for(int j = i+1;j<n;j++){
int cnt = 0;
for(int l = 0;l<4;l++){
if(v[i][l] != v[j][l])cnt += 1;
}
if(cnt == k)res += 1;
}
}
}
else{
int cnt = 1;
map<char,int>mp;
vector<int>pw(4), vs(n);
pw[0] = 1;
pw[1] = 37;
pw[2] = 37*37;
pw[3] = 37*37*37;
for(int l = 0;l<=9;l++)mp['0'+l] = cnt++;
for(int l = 0;l<26;l++)mp['a'+l] = cnt++;
for(int j = 0;j<n;j++){
string to = v[j];
int cont = 0;
for(int i = 0;i<4;i++){
cont += (pw[i]*mp[to[i]]);
}
vis[cont] += 1;
vs[j] = cont;
}
for(int l = 0;l<n;l++){
string to = v[l];
for(int i = 0;i<4;i++){
int u = mp[to[i]];
for(int j = 1;j<=36;j++){
if(u == j)continue;
int cont = vs[l];
cont -= pw[i]*u;
cont += pw[i]*j;
res += vis[cont];
}
}
vis[vs[l]] -= 1;
}
}
cout << res << "\n";
}
/*
*/
signed main()
{
// freopen("seq.in", "r", stdin);
// freopen("seq.out", "w", stdout);
ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
int tt=1;//cin>>tt;
while(tt--)solve();
}
