#include <fstream>

using namespace std;

ifstream fin("catshow.in");
ofstream fout("catshow.out");

int main() {
	int n,a,vs,i;
	fin >> n;
	int v[n-1];
	for (i = 0; i < n; i++) {
		fin >> a;
		vs = 0;
		vs = 15;
		if (a > 1) {
			vs = vs + 9;
		}
		if (a > 2) {
			for (int j = 0; j < a-2; j++) {
				vs = vs + 4;
			}
		}
		v[i] = vs;
	}
	int z[9] = {};
	for (i = 0; i < n; i++) {
		int o = v[i]/10;
		z[o-1] = z[o-1] + 1;
	}

	for (i = 0; i < 9; i++) {
		if (z[i] > 0) {
			fout << (i+1);
			break;
		}
	}
	return 0;
}