#include <bits/stdc++.h>
using namespace std;
int n, m, k, a[110];
int main() {
  cin >> n >> m;
  for (int i = 1; i <= m; ++i) {
    cin >> k;
    for (int j = k; j <= n; ++j)
      if (a[j] == 0) a[j] = k;
  }
  for (int i = 1; i <= n; ++i) cout << a[i] << ' ';
  return 0;
}
