#include <bits/stdc++.h>
using namespace std;
long long int mod = 1e9 + 7;
long long int mul(long long int a, long long int b) {
  return ((a % mod) * (b % mod)) % mod;
}
long long int add(long long int a, long long int b) {
  return ((a % mod) + (b % mod)) % mod;
}
long long int sub(long long int a, long long int b) {
  return ((a % mod) - (b % mod) + mod) % mod;
}
long long int gcdExtended(long long int a, long long int b, long long int *x,
                          long long int *y) {
  if (a == 0) {
    *x = 0, *y = 1;
    return b;
  }
  long long int x1, y1;
  long long int gcd = gcdExtended(b % a, a, &x1, &y1);
  *x = y1 - (b / a) * x1;
  *y = x1;
  return gcd;
}
long long int modInverse(long long int b) {
  long long int x, y;
  long long int g = gcdExtended(b, mod, &x, &y);
  if (g != 1) return -1;
  return (x % mod + mod) % mod;
}
long long int modDivide(long long int a, long long int b) {
  a = a % mod;
  long long int inv = modInverse(b);
  if (inv == -1)
    return -1;
  else
    return (inv * a) % mod;
}
void printa(vector<long long int> &A) {
  for (long long int i = 0; i < A.size(); i++) {
    cout << A[i] << " ";
  }
  cout << '\n';
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int i, t, j, inp, n;
  cin >> n;
  vector<long long int> A;
  for (j = 0; j < n; j++) {
    cin >> inp;
    A.push_back(inp);
  }
  map<long long int, long long int> mp;
  mp[A[0]] = 0;
  vector<vector<long long int>> ans(n);
  ans[0].push_back(A[0]);
  long long int k = 0;
  for (j = 1; j < n; j++) {
    if (A[j] > mp.rbegin()->first) {
      long long int x = mp.rbegin()->first;
      long long int y = mp[x];
      ans[y].push_back(A[j]);
      mp.erase(x);
      mp[A[j]] = y;
    } else if (A[j] < mp.begin()->first) {
      long long int sz = mp.size();
      mp[A[j]] = sz;
      ans[sz].push_back(A[j]);
    } else {
      auto it = mp.lower_bound(A[j]);
      it--;
      long long int x = it->first, y = it->second;
      ans[y].push_back(A[j]);
      mp.erase(x);
      mp[A[j]] = y;
    }
  }
  k = mp.size();
  for (j = 0; j < k; j++) {
    for (i = 0; i < ans[j].size(); i++) {
      cout << ans[j][i] << " ";
    }
    cout << '\n';
  }
  return 0;
}
