#include<iostream>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<map>
#include<iomanip>
#include<queue>
#include<stack>
#include<time.h>
#define rep(i,n)for(int i=0;i<n;i++)
#define int long long
#define ggr getchar();getchar();return 0;
#define prique priority_queue
#define mod 1000000007
#define double long double
using namespace std;
typedef pair<int, int>P;
void pyes() { cout << "Yay!" << endl; }
void pno() { cout << ":(" << endl; }
int gcd(int x, int y) {
	if (y == 0)return x;
	return gcd(y, x % y);
}
int lcm(int x, int y) {
	return x / gcd(x, y) * y;
}
int kai(int x, int y) {
	int res = 1;
	for (int i = x - y + 1; i <= x; i++) {
		res *= i; res %= mod;
	}
	return res;
}
//繰り返し二乗法
int mod_pow(int x, int y, int m) {
	int res = 1;
	while (y) {
		if (y & 1) {
			res = res * x % m;
		}
		x = x * x % m;
		y >>= 1;
	}
	return res;
}
//xCy
int comb(int x, int y) {
	if (y > x)return 0;
	return kai(x, y)* mod_pow(kai(y, y), mod - 2, mod) % mod;
}
int f(int x) {
	int ans = 1;
	for (int i = 1; i <= x; i++) {
		ans *= i;
		ans %= mod;
	}
	return ans;
}
struct edge { int to, cost; };
int n;
int a[114514];
signed main() {
	cin >> n;
	rep(i, n)cin >> a[i];
	int ans = 1;
	rep(i, n) {
		ans *= a[i];
		if (ans % 9 != 0)ans %= 9;
	}
	if (n == 0)cout << 0 << endl;
	else if (ans % 9 == 0)cout << 9 << endl;
	else cout << ans % 9 << endl;
	ggr
}