#include<iostream>
#include<vector>
#include<string>
#include<cstring>
#include<algorithm>
#include<map>
#include<tuple>
#include<array>
using namespace std;
void solve(){
	int n;
	cin>>n;
	map<tuple<int,string,string,int>,int>idx;
	vector<string>arr(n+1);
	for(int i=1;i<=n;i++){
		cin>>arr[i];
	}
	for(int i=1;i<=n;i++){
		for(int j=i+1;j<=n;j++){
			if((int)arr[i].size()!=(int)arr[j].size())continue;
			else{
				int cnt1=0;
				int pos=0;
				for(int k=0;k<(int)arr[i].size()-1;k++){
					if((arr[i][k]!=arr[j][k])&&(arr[i][k+1]!=arr[j][k+1])){
						cnt1++;
						pos=k;
					}
				}
				string a2=arr[i].substr(min(pos+2,(int)arr[i].size()),(int)arr[i].size());
				string b2=arr[j].substr(min(pos+2,(int)arr[j].size()),(int)arr[j].size());
				string a1=arr[i].substr(0,pos-0);
				string b1=arr[j].substr(0,pos-0);
				if((cnt1!=1)||((a1!=b1)&&(a2!=b2)))continue;
				// cout<<arr[i]<<' '<<arr[j]<<endl;
				// cout<<a1<<' '<<a2<<endl;
				// cout<<b1<<' '<<b2<<endl;
				// cout<<"......"<<endl;
				string a=arr[i].substr(pos,2);
				string b=arr[j].substr(pos,2);
				if(a>b)swap(a,b);
				tuple<int,string,string,int>t={pos-0,a,b,(int)arr[i].size()-pos-2};
				// cout<<a<<" "<<b<<endl;
				idx[t]++;
			}
			
		}
	}
	int ans=0;
	for(auto t:idx){
		if(t.second==1)ans++;
		tuple<int,string,string,int>temp=t.first;
		int p1,p2;
		string a,b;
		tie(p1,a,b,p2)=temp;
		// cout<<p1<<' '<<a<<' '<<b<<' '<<p2<<endl;
	}
	cout<<ans<<endl;
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	solve();
}