#include <bits/stdc++.h>
using namespace std;
#define int long long
constexpr int N = 1e5 + 7, M = 11;
constexpr int inf = 1E18, mod = 1e9 + 7;
inline void Main() {
    int n; cin >> n;
    int mx = 0;
    vector<int> dp(10);
    for (int i = 0; i < n; i ++) {
        string s; cin >> s;
        char a = s[0] - '0', b = s.back() - '0';
        dp[b] = max(dp[b], dp[a] + 1);
        mx = max(mx, dp[b]);
    }
    cout << n - mx << '\n';
}
signed main() {    
    cin.tie(nullptr)->sync_with_stdio(false);
    int T = 1; 
    while(T --) Main();
    return 0;
}