#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) for(int i = (n) - 1; (i) >= 0; --i)
#define SZ(n) (int)(n).size()
#define ALL(n) (n).begin(), (n).end()
#define MOD LL(1e9 + 7)
#define INF 1000000
using namespace std;
typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PI;


int main() {
	int n;
	cin >> n;
	LL ans = LLONG_MAX;
	REP(i, n) {
		string v;
		cin >> v;
		REP(i, v.size()) {
			if (v[i] >= 'A') {
				v[i] -= 'A' - 10;
			}
			else {
				v[i] -= '0';
			}
		}
		int t = 0;
		REP(i, v.size()) {
			t = max(t, int(v[i]));
		}
		t++;
		LL res = 0;
		REP(i, v.size()) {
			res = res * t + v[i];
		}
		ans = min(ans, res);
	}
	cout << ans << endl;
	return 0;
}