#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=200005;
int n;
string s[1505];
map<pair<string,string>,map<pair<string,string>,int> > nums;
void solve(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>s[i];
	}
	for(int i=1;i<=n;i++){
		for(int j=i+1;j<=n;j++){
			string m1="",m2="";
			int pre=-1;int f=0,js=-1;
			bool y=1;
			for(int k=0;k<s[i].length();k++){
		//	cout<<s[i][k]<<" "<<pre<<" "<<js<<endl;
		//cout<<k<<" ";
				if(s[i][k]==s[j][k]&&f){
					f=0;
					js=k-1;
					if(k-pre!=2){
						y=0;
						break;
					}
				}
				
				if(s[i][k]!=s[j][k]){
					m1+=s[i][k];
					m2+=s[j][k];
					f=1;
					if(js>=0){
						y=0;
						break;
					}
					
					if(pre==-1)
						pre=k;				
				}
				
			}
		//	if(pre==-1)pre=0;
		//	cout<<endl;
			if(js==-1){
				if(s[i].length()-pre!=2){
					y=0;
				}
				js=s[i].length()-1;
			}
			//cout<<pre<<" "<<js<<endl;
			if(y){
			//	cout<<js<<" ";
			//	if(m1>m2)swap(m1,m2);
				string p1=s[i].substr(0,pre);
				string p2=s[i].substr(js,s[i].length()-js+1);
			//	cout<<s[i]<<" "<<s[j]<<"p1"<<p1<<"p"<<p2<<"p2"<<endl;
				nums[make_pair(m1,m2)][make_pair(p1,p2)]++;
			//	nums[make_pair(m2,m1)][make_pair(p1,p2)]++;
			}	
		}
	}
	int ans=0;
	for(auto it:nums){
		//cout<<it.first.first<<" "<<it.first.second<<endl;
		//if(it.second.size()==1){
			for(auto o:it.second){
				if(o.second==1){
					//cout<<o.first.first<<it.first.first<<o.first.second<<endl;
					ans++;
				}
			}
		//}
	//	cout<<ans/2<<endl;
	}
	cout<<ans;
	return;
}
signed main() {
	//ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("in.txt","r",stdin);
	//freopen("out.txt","w",stdout);
	int t=1;
	//cin>>t;
	while(t--){
		solve();
	}
    return 0;
}