#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define endl '\n'
#define yes cout << "YES\n";
#define no cout << "NO\n";
#define fr(n) for(ll i = 0 ; i < n ; i++)
#define frj(n) for(ll j = 0 ; j < n ; j++)
#define ll long long
#define files    freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#define Ksakkary ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

const ll mod = 1e9 + 7;

using namespace std;


ll gcd(ll a, ll b) {
    if (b == 0) return a;
    return gcd(b, a % b);
}

ll mult(ll a, ll b) {
    return ((a % mod) * (b % mod)) % mod;
}

ll add(ll a, ll b) {
    return ((a % mod) + (b % mod)) % mod;
}

ll subtract(ll a, ll b) {
    return ((a % mod) - (b % mod) + (2 * mod)) % mod;
}

const unsigned ll N = 2e6 + 5;

int knightX[] = {-2, -2, 2, 2, 1, 1, -1, -1};
int knighty[] = {-1, 1, -1, 1, -2, 2, -2, 2};

int dx[] = {1, 0, -1, 0, -1, -1, 1, 1};
int dy[] = {0, -1, 0, 1, -1, 1, -1, 1};
char di[] = {'D', 'L', 'U', 'R'};
int n , m ;
vector<vector<pair<int,int>>> adj;
int dfs(int x , int h){
    if(!adj[x].empty()) {
        auto p = upper_bound(all(adj[x]), make_pair(h, m+1));
        if (p != adj[x].end()) {

            return dfs((*p).second, (*p).first);
        }
    }
    return x;
}
void solve() {
    cin >> n >> m;
    adj = vector<vector<pair<int,int>>> (n+1);
    fr(m){
        int x ; cin >> x;
        adj[x].emplace_back(i+1, x+1);
        adj[x+1].emplace_back(i+1, x);
    }
    vector<int> ans (n);
    for(int i = 1 ; i <= n ; i++){

        ans[dfs(i , 0)-1] = i;
    }
    for(auto i : ans) cout << i << endl;
}

int main() {
    Ksakkary
#ifndef ONLINE_JUDGE
    files
#endif
    // sieve();
    ll t = 1;
//    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}