#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
using std::chrono::high_resolution_clock;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int>pi;
typedef pair<ll, ll>pl;
typedef vector<pi>vpi;
typedef vector<pl>vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<string> vs;
const double PI = acos(-1);
const int oo = 1e9 + 7;
const int MOD = 1e9 + 7;
const int N = 1e6 + 1;
#define endl '\n'
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define read(v) for (auto& it : v) scanf("%d", &it);
#define readL(v) for (auto& it : v) scanf("%lld", &it);
#define print(v) for (auto it : v) printf("%d ", it); puts("");
#define printL(v) for (auto it : v) printf("%lld ", it); puts("");
auto Time() {
	return high_resolution_clock::now();
}
ll calc(string s) {
	while (s.size() > 1) {
		int sum = 0;
		for (auto& it : s)
			sum += (it - '0');
		s = to_string(sum);
	}
	return stoll(s);
}
void solve() {
	int n;
	scanf("%d", &n);
	vl v(n);
	readL(v);
	ll ans = 0;
	for (auto& it : v)
		ans += calc(to_string(it));
	ans = calc(to_string(ans));
	printf("%lld\n", ans);
}
int t = 1;
int main() {
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
#endif
	//scanf("%d", &t);
	while (t--) solve();
}