#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define sz size()
#define ff first
#define ss second
#define pb push_back
#define pii pair <int, int>
#define dur exit(0)
#define dur1 return(0)
const int N = 2e5 + 5;
char a[N];
int main () {
// freopen ("input.txt", "r", stdin);
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int n;
cin >> n;
bool subtask = 0;
for (int i = 1; i <= n; ++i) {
int x;
cin >> x;
a[i] = char(x + 48);
if (i > 1) {
if (a[i - 1] != a[i]) subtask = 1;
}
}
if (!subtask) {
// cout << a[1];
// return 0;
if (a[1] == '9') {
int cyk = 9, ayyr = 0, jog = 1;
for (int i = 2; ; ++i) {
jog *= 10;
ayyr *= 10;
ayyr++;
cyk *= 10;
if (jog + ayyr >= n) {
break;
}
}
cout << cyk - ayyr;
}
else {
if (a[1] != '0') cout << a[1];
else cout << 1;
if (a[1] != '0' and n == 1) return 0;
int jog = 1;
for (int i = 2; ; ++i) {
jog *= 10;
cout << 0;
if (jog >= n) {
break;
}
}
}
return 0;
}
else {
for (int i = 1; ; ++i) {
int idx = 0, bol = 0;
for (int j = i; j <= i + n - 1; ++j) {
string jog = to_string(j);
idx++;
int ok = 0;
for (char k : jog) {
if (k == a[idx]) {
ok = 1;
break;
}
}
if (!ok) {
bol = 1;
break;
}
}
if (!bol) {
return cout << i, 0;
}
}
}
}
