#define _USE_MATH_DEFINES
#include<stdio.h>
#include<iostream>
#include<vector>
#include<cmath>
#include<algorithm>
#include<map>
#include<set>
#include<sstream>
#include<cstring>
#include<numeric>
#include<limits.h>
#include<time.h>
using namespace std;


set<int> to;


void found(vector<char> cur) {
    to.erase(cur[cur.size() - 1]);
    for (int i = cur.size() - 4; i < cur.size(); i++) {
        for (int len = 1; len <= cur.size() - i; len++) {
            int toDel = 0;
            for (int j = 0; j < len; j++) {
                toDel *= 10;
                toDel += cur[i + j];
            }
            to.erase(toDel);
        }
    }
}


int res = LONG_MAX;

void solve() {
    for (int i = 0; i <= 9999; i++) {
        to.insert(i);
    }

    srand(time(0));
    vector<char> cur;
    for (int i = 0; i < 4; i++) {
        cur.push_back(rand() % 10);
        to.erase(cur[i]);
    }
    found(cur);
    while (to.size() != 0) {
        cur.push_back(rand() % 10);
        found(cur);
    }

    if (cur.size() < res) {
        res = cur.size();
        for (int i = 0; i < res; i++) {
            printf("%c", cur[i]);
        }
        printf("\n\n");
    }
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif
    freopen("output.txt", "w", stdout);


    while (true) {
        solve();
    }


    return 0;
}