#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 2000001;
vector<map<pair<char,char>,int>> tri;
int bes[MX];
int nex = 1, ans;
void ins(string t) {
int cur = 0, res = 0;
F0R(i,sz(t)) {
pair<char,char> p = {t[i],t[sz(t)-1-i]};
if (!tri[cur].count(p)) {
tri[cur][p] = nex ++;
tri.pb(map<pair<char,char>,int>());
}
cur = tri[cur][p];
res = max(res,bes[cur]);
}
ans = max(ans,bes[cur] = res+1);
}
int N;
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
tri.pb(map<pair<char,char>,int>());
cin >> N;
F0R(i,N) {
string s; cin >> s;
ins(s);
}
cout << ans;
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
