#include <bits/stdc++.h>
#define rep(a,b,c) for(int a=b; a<c; a++)
#define repa(a,b) for(auto a:b)
#define fi first
#define se second
#define pii pair<int, int>
#define ll long long
#define endl "\n"
using namespace std;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, d, ans=0;
cin>>n>>d;
string s[n], t;
map<string,int> ss;
rep(i,0,n){
cin>>s[i];
t=s[i];
rep(k,0,4){
rep(j,0,10) if(j+'0'!=s[i][k]) t[k]=j+'0', ans+=ss[t];
rep(j,0,26) if(j+'a'!=s[i][k]) t[k]=j+'a', ans+=ss[t];
t[k]=s[i][k];
}
ss[s[i]]++;
}
cout<<ans<<endl;
}
