#include <bits/stdc++.h>

using namespace std;

#define LOG(...) fprintf(stderr,__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort(ALL(c))
#define RSORT(c) sort(RALL(c))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

inline int c2i(char c) {
    if (c <= '9') {
        return c - '0';
    } else {
        return c - 'A' + 10;
    }
}

int main() {
    int n;
    cin >> n;

    ll mi = LLONG_MAX;
    REP(i, n) {
        string s;
        cin >> s;
        set<char> cs;
        REP(j, s.length()) {
            cs.insert(s[j]);
        }

        int base = c2i(*cs.rbegin()) + 1;
        ll res = 0;
        REP(j, s.length()) {
            res = res*base + c2i(s[j]);
        }
        mi = min(mi, res);
    }
    cout << mi << endl;
}