#include <iostream>
#include <string>
#include <algorithm>
#include <limits>

using namespace std;

long long valueOf(const string& s, int radix) {
	long long result = 0;
	for (size_t i = 0; i < s.size(); ++i) {
		char ch = s[i];
		int digit = ch >= 'A' ? ch - 'A' + 10 : ch - '0';
		result = result * radix + digit;
	}
	return result;
}

int main() {
	int n;
	cin >> n;
	long long minValue = numeric_limits<long long>::max();
	for (int i = 0; i < n; ++i) {
		string v;
		cin >> v;
		char maxDigitChar = *max_element(v.begin(), v.end());
		int maxDigit = maxDigitChar >= 'A' ? maxDigitChar - 'A' + 10 : maxDigitChar - '0';
		int radix = maxDigit + 1;
		minValue = min(minValue, valueOf(v, radix));
	}
	cout << minValue << endl;
	return 0;
}