#include <bits/stdc++.h>
using namespace std;
int n, ans;
int a[1005];
int cnt[5];
int f[5][5]; // f[i][j]: i 区域有多少个 j
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        cnt[a[i]]++;
    }
    cnt[2] += cnt[1];
    cnt[3] += cnt[2];
    // 1: cnt[0]+1 ~ cnt[1]
    // 2: cnt[1]+1 ~ cnt[2]
    // 3: cnt[2]+1 ~ cnt[3]
    for (int i = 1; i <= 3; i++)
        for (int j = cnt[i - 1] + 1; j <= cnt[i]; j++)
            f[i][a[j]]++;
    int now;
    ans = 0;
    // 1 <-> 2
    now = min(f[1][2], f[2][1]);
    ans += now;
    f[1][2] -= now;
    f[2][1] -= now;
    // 2 <-> 3
    now = min(f[2][3], f[3][2]);
    ans += now;
    f[2][3] -= now;
    f[3][2] -= now;
    // 1 <-> 3
    now = min(f[1][3], f[3][1]);
    ans += now;
    f[1][3] -= now;
    f[3][1] -= now;
    // 三元交换
    now = 0;
    for (int i = 1; i <= 3; i++)
        for (int j = 1; j <= 3; j++)
            if (i != j)
                now += f[i][j];
    cout << ans + now / 3 * 2 << endl;
    return 0;
}