#include <bits/stdc++.h>
using namespace std;
random_device rd;
knuth_b gen(rd());
const int MAXN = 1e5 + 10;
int K,vetor[MAXN],freq[10][2];
int pretest[20];
int check(int ini){
for(int i = ini,ptr = 1;ptr <= K;i++,ptr++){
if(i == 0 && vetor[ptr] == 0) continue;
int copia = i;
while(copia != 0 && copia % 10 != vetor[ptr]) copia /= 10;
if(copia == 0) return 0;
}
return 1;
}
int pretesting(int ini){
for(int j = 0;j<19;j++){
int ptr = pretest[j];
int i = vetor[ptr];
if(i == 0 && vetor[ptr] == 0) continue;
int copia = i;
while(copia != 0 && copia % 10 != vetor[ptr]) copia /= 10;
if(copia == 0) return 0;
}
return 1;
}
int main(){
cin >> K;
for(int i = 1;i<=K;i++){
cin >> vetor[i];
freq[vetor[i]][1]++;
}
for(int i = 0;i<19;i++){
int aleatorio = 1 + (gen() % K);
pretest[i] = aleatorio;
}
if(K <= 1000){
for(int i = 1;i<=1000000;i++){
if(!pretesting(i)) continue;
if(check(i)){
cout << i << endl;
return 0;
}
}
}
if(vetor[1] == 9){
int geratriz = 8;
while(true){
if(check(geratriz + 1)){
cout << geratriz + 1 << endl;
return 0;
}
geratriz *= 10;
geratriz += 8;
}
}
else if(vetor[1] == 0){
int ini = 1;
while(true){
if(check(ini)){
cout << ini << endl;
return 0;
}
ini *= 10;
}
}
else{
int ini = vetor[1];
while(true){
if(check(ini)){
cout << ini << endl;
return 0;
}
ini *= 10;
}
}
return 0;
}
