#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 1e5 + 10;

int n;
int a[N];
int f[N], g[10];

string _to_string(int x) {
    string res = "";
    while (x) res = char(x % 10 + '0') + res, x /= 10;
    return res;
}

int main() {
    cin >> n;
    for (int i = 1; i <= n; i ++ ) cin >> a[i];

    int res = 0;
    for (int i = 1; i <= n; i ++ ) {
        string t = _to_string(a[i]);
        int head = t[0] - '0', tail = t[t.size() - 1] - '0';
        f[i] = 1;
        f[i] = max(f[i], g[head] + 1);
        g[tail] = max(g[tail], f[i]);
        res = max(res, f[i]);
    }

    cout << n - res;

    return 0;
}