#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
void print_width(long long x) {
  std::cout << std::fixed;
  std::cout << std::setprecision(x);
}
bool sortinrev(const pair<long long, long long> &a,
               const pair<long long, long long> &b) {
  return (a.first > b.first);
}
long long gcd(long long a, long long b) { return (b == 0 ? a : gcd(b, a % b)); }
long long lcm(long long a, long long b) { return ((a * b) / gcd(a, b)); }
long long isPrime(long long n) {
  if (n < 2) return 0;
  if (n < 4) return 1;
  if (n % 2 == 0 or n % 3 == 0) return 0;
  for (long long i = 5; i * i <= n; i += 6)
    if (n % i == 0 or n % (i + 2) == 0) return 0;
  return 1;
}
long long nCr(long long n, long long r) {
  if (r > n - r) r = n - r;
  long long ans = 1;
  long long i;
  for (i = 1; i <= r; i++) {
    ans *= n - r + i;
    ans /= i;
  }
  return ans;
}
long long modexpo(long long x, long long p) {
  long long res = 1;
  x = x % mod;
  while (p) {
    if (p % 2) res = res * x;
    p >>= 1;
    x = x * x % mod;
    res %= mod;
  }
  return res;
}
long long sti(string s) {
  long long ans = 0;
  long long p = 1;
  for (long long i = s.size() - 1; i >= 0; i--) {
    ans = (ans + ((long long)(s[i] - '0') * p) % mod) % mod;
    p = (p * 10) % mod;
  }
  return ans;
}
void time() {}
const long long N = 1e6 + 5;
const long long despacito = 1e9 + 7;
long long mxlvl = 1;
map<long long, vector<string>> m;
void dfs(stringstream &second, string cur, long long lvl) {
  mxlvl = (mxlvl >= lvl ? mxlvl : lvl);
  m[lvl].push_back(cur);
  string num;
  getline(second, num, ',');
  long long no = stoi(num);
  for (long long i = 1; i <= no; ++i) {
    string nxt;
    getline(second, nxt, ',');
    dfs(second, nxt, lvl + 1);
  }
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  string s;
  cin >> s;
  stringstream second(s);
  string cur;
  while (getline(second, cur, ',')) {
    dfs(second, cur, 1);
  }
  cout << mxlvl << "\n";
  for (auto it : m) {
    for (auto j : it.second) {
      cout << j << " ";
    }
    cout << "\n";
  }
  return 0;
}
