#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
 
using namespace std;
 
#if __GNUC__
#include <tr1/unordered_map>
#include <tr1/unordered_set>
using namespace tr1;
#else
#include <unordered_map>
#include <unordered_set>
#endif

#ifdef __GNUC__
template <class T> int popcount(T n);
template <> int popcount(unsigned int n) { return __builtin_popcount(n); }
template <> int popcount(int n) { return __builtin_popcount(n); }
template <> int popcount(unsigned long long n) { return __builtin_popcountll(n); }
template <> int popcount(long long n) { return __builtin_popcountll(n); }
#else
#define __typeof__ decltype
template <class T> int popcount(T n) { return n ? 1 + popcount(n & (n - 1)) : 0; }
#endif
 
#define rep(i, n) for (int i = 0; i < (int)n; ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
 
 
template <class T> void max_swap(T& a, const T& b) { a = max(a, b); }
template <class T> void min_swap(T& a, const T& b) { a = min(a, b); }
 
typedef long long ll;
typedef pair<int, int> pint;
 
template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
 
template <class T> void print(T a, int n, int br = 1, const string& deli = ", ") { cout << "{ "; for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } cout << " }"; while (br--) cout << endl; }
template <class T> void print(const vector<T>& v, int br = 1, const string& deli = ", ") { print(v, v.size(), br, deli); }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }

template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T, class U> void input(T& a, U& b, int n) { for (int i = 0; i < n; ++i) cin >> a[i] >> b[i]; }
 
const double EPS = 1e-8;
const double PI = acos(-1.0);
const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };
bool valid_pos(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }



typedef pair<ll, ll> P;
ll enc(int* s)
{
    ll res = 0;
    for (int i = 0; i < 5; ++i)
        res = (res << 8) | s[i];
    return res;
}
P encode(int* s)
{
    return P(enc(s + 1), enc(s + 5));
}


int n, a[128];
 
int res, possi_max;
int sack[11];
set<P> memo[101];
void dfs(int d)
{
    if (res == possi_max || sack[10] + (n - d) <= res || memo[d].count(encode(sack)))
        return;
    else if (d == n)
    {
        res = sack[10];
        return;
    }

    memo[d].insert(encode(sack));

    for (int i = 10 - a[d]; i >= 0; --i)
    {
        if (sack[i] > 0)
        {
            int j = a[d] + i;
 
            --sack[i];
            ++sack[j];
 
            dfs(d + 1);
 
            ++sack[i];
            --sack[j];
        }
    }
}
int rem()
{
    int s[10] = { };
    for (int i = 0; i < n; ++i)
        ++s[a[i]];

    int ten = 0;
    for (int i = 1; i < 5; ++i)
    {
        int t = min(s[i], s[10 - i]);
        s[i] -= t;
        s[10 - i] -= t;
        ten += t;
    }
    ten += s[5] / 2;
    s[5] %= 2;

    n = 0;
    for (int i = 1; i <= 9; ++i)
        while (s[i]-- > 0)
            a[n++] = i;

    return ten;
}
int solve()
{
    sort(a, a + n, greater<int>());
 
    for (int i = 0; i < 100; ++i)
        memo[i].clear();

    possi_max = accumulate(a, a + n, 0) / 10;
    res = 0;
    dfs(0);
 
    return res;
}
int main()
{
    ios::sync_with_stdio(false);
 
    sack[0] = 114514;
    while (cin >> n, n)
    {
        input(a, n);
        int t = rem();
        int res = solve() + t;
        cout << res << endl;
    }
}

Measured memory_bytes: 0