#include <bits/stdc++.h>
using namespace std;

const int N = 2e3 + 5;

string s[N];

int n;

#define pss pair <string, string>

vector < pss > T[25][25];

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; ++ i) 
    cin >> s[i];

    for(int i = 1; i <= n; ++ i) {
        int l = s[i].size();
        for(int j = i + 1; j <= n; ++ j) {
            if(s[i].size() != s[j].size())
            continue;
            vector <int> fid;
            for(int k = 0; k < l; ++ k)
            if(s[i][k] != s[j][k]) {
                fid.push_back(k);
            }
            if(fid.size() != 2) {
                continue;
            }
            if(fid[0] + 1 != fid[1]) {
                continue;
            }
            string a = "", b = "";
            a += s[i][fid[0]];
            a += s[i][fid[1]];

            b += s[j][fid[0]];
            b += s[j][fid[1]];
            
            if(a > b) swap(a, b);
            T[fid[0]][l - 1 - fid[1]].push_back(make_pair(a, b));
        }
    }

    int ans = 0;

    for(int i = 0; i < 25; ++ i) {
        for(int j = 0; j < 25; ++ j) {
            if(!T[i][j].size()) continue;
            sort(T[i][j].begin(), T[i][j].end());

            for(int k = 0; k < (int) T[i][j].size(); ++ k) {
                if(k + 1 == T[i][j].size()) {
                    ++ ans; break;
                }

                if(T[i][j][k] == T[i][j][k + 1]) {
                    int now = k;
                    while(k < (int) T[i][j].size() && T[i][j][k] == T[i][j][now]) {
                        ++ k;
                    }
                    -- k;
                } else ++ ans;
            }

        }
    }
    cout << ans << endl;
}