#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll; const int inf = 0x3fffffff; const ll INF = 0x3fffffffffffffff;
template<class T> inline bool chmax(T& a,T b){ if(a<b){a=b;return 1;}return 0; }
template<class T> inline bool chmin(T& a,T b){ if(a>b){a=b;return 1;}return 0; }
//template end



int main(){
    int n; scanf("%d",&n);
    int ans=1;
    rep(i,0,n){
        ll tmp; scanf("%lld",&tmp);
        if(tmp==0){printf("0\n"); return 0;}
        ans*=(tmp%9); ans%=9;
    }
    if(ans==0)ans=9;
    printf("%d\n",ans);
    return 0;
}