const int INF = (int)1e9 + 7;

int solve()
{
    int m, n;
    scanf("%d %d", &m, &n);
    vector<int> a(n);
    for (int i = 0; i < n; ++i)
    {
        scanf("%d", &a[i]);
        --a[i];
    }
    sort(all(a));
    vector<vi> dp(2, vi(m));
    for (int i = 0; i < n; ++i)
    {
        dp[0][i] = abs(a[0] - i);
    }
    for (int i = 1; i < n; ++i)
    {
        int cmin = dp[0][0];
        for (int j = 0; j < i; ++j)
        {
            dp[1][j] = INF;
            cmin = min(cmin, dp[0][j]);
        }
        for (int j = i; j < m; ++j)
        {
            dp[1][j] = cmin + abs(a[i] - j);
            cmin = min(cmin, dp[0][j]);
        }
        swap(dp[0], dp[1]);
    }
    int ans = dp[0][0];
    for (int i = 0; i < m; ++i)
        ans = min(ans, dp[0][i]);
    printf("%d\n", ans);
    return 0;
}