#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

void bins(int col, int minRow, int maxRow);

int n;
vector<string> vs(2e5);
long long ans;

int main() {
    cin >> n;
    vs.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> vs[i];
    }
    // sort(vs.begin(), vs.end());
    
    // for (int i = 0; i < n; i++) cout << vs[i] << endl;
    
    bins(0, 0, n-1);
    
    cout << ans << endl;
    return 0;
}

void bins(int col, int minRow, int maxRow) {
    int lRow = minRow;
    for (int row = minRow; row <= maxRow; row++) {
        if (vs[lRow].size() <= col) {
            lRow = row; continue;
        }
        if (vs[row].size() <= col) {
            lRow = row; continue;
        } else if (vs[row][col] == vs[lRow][col]) {
            continue;
        }
        int len = row - lRow;
        if (len == 1) {
            ans += (long long)vs[lRow].size() - (long long)col;
        } else {
            long long lp = 1, rp = len;
            while (lp <= rp) {
                ans += lp * rp * (lp == rp ? 1LL : 2LL);
                lp++; rp--;
            }
            bins(col + 1, lRow, row - 1);
        }
        lRow = row;
    }
    if (vs[lRow].size() > 0) {
        int row = maxRow + 1;
        int len = row - lRow;
        if (len == 1) {
            ans += (long long)vs[lRow].size() - (long long)col;
        } else {
            long long lp = 1, rp = len;
            while (lp <= rp) {
                ans += lp * rp * (lp == rp ? 1LL : 2LL);
                lp++; rp--;
            }
            bins(col + 1, lRow, row - 1);
        }
    }
}