#include <iostream>
#include <string>
#include <cmath>

#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define ull unsigned long long
using namespace std;

// 0=48 9=57 A=65 Z=90

int ctoi(char c)
{
	if(c <= 58) return (int)c-48;
	else return (int)c-55; // -65+10
}

int main(void)
{
	int n, num, dig;
	ull sum, ans;
	string s, a;
	char c, mc = 0;
	cin >> n;

	ans = 18446744073709551614;
	rep(i, 0, n) {
		cin >> s;
		mc = 0;
		rep(i, 0, s.size()) {
			c = s[i];
			if (c > mc) mc = c;
		}
		dig = ctoi(mc + 1);

		sum = 0;
		rep(i, 0, s.size()) {
			c = s[s.size() - 1 - i];
			num = ctoi(c);
			if(n) sum += num * (ull)pow(dig, i);
		}
		if(sum < ans) {
			ans = sum;
		}
	}

	printf("%llu\n",ans);
	return 0;
}