#include <iostream>
#include <string>
#include <vector>
using namespace std;
const long long INF = 5000000000000000000;
int main(){
	int N;
	cin >> N;
	vector<string> V(N);
	for (int i = 0; i < N; i++){
		cin >> V[i];
	}
	long long ans = INF;
	for (int i = 0; i < N; i++){
		int L = V[i].size();
		vector<int> d(L);
		for (int j = 0; j < L; j++){
			if (isdigit(V[i][j])){
				d[j] = V[i][j] - '0';
			} else {
				d[j] = V[i][j] - 'A' + 10;
			}
		}
		int b = 2;
		for (int j = 0; j < L; j++){
			b = max(b, d[j] + 1);
		}
		long long num = 0;
		for (int j = 0; j < L; j++){
			num = num * b + d[j];
		}
		ans = min(ans, num);
	}
	cout << ans << endl;
}