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

using namespace std;

const int N = 1e5 + 10;

int f[N];
char a[N];
int b[N];
int g[10];

int main()
{
    int n;
    cin >> n;


    char str[20];
    for (int i = 1; i <= n; i++)
    {
        cin >> str;
        a[i] = str[0] - '0';
        b[i] = str[strlen(str) - 1] - '0';
    }

    for (int i = 1; i <= n; i++)
    {
        f[b[i]] = max(f[b[i]], f[a[i]] + 1);
    }
    int res = 0;
    for (int i = 0; i <= 9; i++)
        res = max(res, f[i]);

    cout << n - res << endl;

    return 0;
}