#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define R cin>>
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

ll C(char c, int n) {
  int d;
  if(isdigit(c)) {
    d=c-'0';
    if(d>=n) return -1;
    return d;
  }
  d=c-'A';
  d+=10;
  if(d>=n) return -1;
  return d; 
}

int main() {
  int n;
  cin >> n;
  string s[n];
  rep(i,n) cin >> s[i];
  ll ans=MAXL;
  rep(j,n) {
    for(ll i=2; i<=36; i++) {
      ll a=0,k=s[j].size()-1,x=1;
      bool ck=true;
      while(k>=0) {
	ll d=C(s[j][k],i);
	if(d==-1) {
	  ck=false;
	  break;
	}
	a+=d*x;
	x*=i;
	k--;
      }
      if(ck) ans=min(ans,a);
    }
  }
  cout << ans << endl;
  return 0;
}