#include <bits/stdc++.h>
using namespace std;
#define rep(i,N) for(int i=0;i<int(N);++i)
#define rep1(i,N) for(int i=1;i<int(N);++i)
#define all(a) (a).begin(),(a).end()
#define print(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<_<<", "; cerr<<"]"<<endl; }
#define printpair(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<"{"<<_.first<<","<<_.second<<"}"<<", "; cerr<<"]"<<endl; }

typedef long long ll;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

const int INF = 1e9;
const ll INFLL = 1e18;
const ll MOD = 1e9+7;
const double PI = acos(-1.0);

const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};

/*------------------------------------/
for library*/

/*------------------------------------*/

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    int N;
    cin>>N;
    vector<ll> P(N);
    rep(i,N){
        cin>>P[i];
    }
    int K = 1;
    rep(i,N){
        string x = to_string(P[i]);
        int tmp = 0;
        rep(j,(int)x.size()){
            tmp += x[j] - '0';
        }
        K *= tmp;
        while(to_string(K).size()>1){
            string K_st = to_string(K);
            int cnt = 0;
            rep(j,(int)K_st.size()){
                cnt += K_st[j]-'0';
            }
            K = cnt;
        }
    }
    cout<<K<<endl;
}