#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef unsigned long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;

const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-10;

ll power(ll x, ll n) {
	if (n == 0) return 1;
	ll res = power(x * x, n / 2);
	if (n & 1) res = res * x;
	return res;
}

ll to_num(string s, int dec) {
	ll res = 0;
	
	REP(i, s.size()) res += power(dec, i) * s[i];
	
	return res;
}

int main() {
	int n;
	cin >> n;
	
	ll ans = -1;
	
	REP(i, n) {
		string str;
		cin >> str;
		
		REP(j, str.size()) {
			if (isdigit(str[j])) str[j] = str[j] - '0';
			else str[j] = str[j] - 'A' + 10;
		}
		
		int ma = 0;
		REP(j, str.size()) chmax(ma, str[j]);
		
		reverse(ALL(str));
		
		ll now = -1;
		FOR(j, ma + 1, 37) chmin(now, to_num(str, j));
		
		chmin(ans, now);
	}
	cout << ans << endl;
	return 0;
}