// #define DEBUGGING
#include <bits/stdc++.h>
#define endl '\n'
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()
template <typename T> using V = std::vector<T>;
template <typename T> using VV = V<V<T>>;
using ll = std::int64_t;
using ull = std::uint64_t;
using PLL = std::pair<ll, ll>;
using TLL = std::tuple<ll, ll, ll>;
template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return std::max(low, std::min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { return t = clamp(t, low, high); }
namespace init__ { struct InitIO { InitIO() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(30); } } init_io; }
#define mv_rec make_v(init, tail...)
template <typename T> T make_v(T init) { return init; }
template <typename T, typename... Tail> auto make_v(T init, size_t s, Tail... tail) { return V<decltype(mv_rec)>(s, mv_rec); }
#undef mv_rec
using namespace std;
#ifdef DEBUGGING
#include "../../debug/debug.cpp"
#else
#define DEBUG(...) 0
#define DEBUG_SEPARATOR_LINE 0
#endif

ll sum1(ll n) { return n * (n + 1) / 2; }

ll sum2(ll n) { return n * (n + 1) * (2 * n + 1) / 6; }

int main() {
    ll N;
    cin >> N;
    V<string> vs(N);
    for (auto &&s : vs) cin >> s;
    queue<PLL> rq;
    rq.emplace(0, N);
    
    ll ans = 0;
    ll idx = 0;
    for (ll idx = 0; rq.size(); idx++) {
        queue<PLL> nrq;
        while (rq.size()) {
            ll l, r;
            tie(l, r) = rq.front();
            rq.pop();
            V<PLL> rngs;  // remove vs[i].size() <= idx
            ll cl = -1;
            for (ll i = l; i <= r; i++) {
                ll len = (i == r ? -1 : vs[i].size());
                if (len <= idx && cl != -1) {
                    rngs.emplace_back(cl, i);
                    cl = -1;
                } else if (idx < len && cl == -1) {
                    cl = i;
                }
            }
            for (PLL p : rngs) {
                ll l, r;
                tie(l, r) = p;
                ll cl = l;
                char cur = vs[l][idx];
                for (ll i = l + 1; i <= r; i++) {
                    char nxt = (i == r ? 0 : vs[i][idx]);
                    if (cur == nxt) continue;
                    ll len = i - cl;
                    ans += (len + 1) * sum1(len) - sum2(len);
                    nrq.emplace(cl, i);
                    cl = i;
                    cur = nxt;
                }
            }
        }
        rq = move(nrq);
    }

    cout << ans << endl;
    return 0;
}