#include <bits/stdc++.h>
using namespace std;
void edit(vector<int> &skill, int n) {
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    skill.push_back(x);
  }
}
bool cmp(pair<long long, long long> p1, pair<long long, long long> p2) {
  if (p1.second > p2.second) return true;
  if (p1.second < p2.second) return false;
  if (p1.first > p2.first)
    return true;
  else
    return false;
}
void editl(vector<long long> &skill, long long n) {
  for (long long i = 0; i < n; i++) {
    long long x;
    cin >> x;
    skill.push_back(x);
  }
}
void editpl(vector<pair<long long, long long>> &skill, long long n) {
  for (long long i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    skill.push_back({x, y});
  }
}
long long nextPowerOf2(long long n) {
  n--;
  n |= n >> 1;
  n |= n >> 2;
  n |= n >> 4;
  n |= n >> 8;
  n |= n >> 16;
  n++;
  return n;
}
bool ispalin(string s) {
  long long j = s.size() - 1, i = 0;
  while (i < j) {
    if (s[i] != s[j]) return false;
    ++i;
    --j;
  }
  return true;
}
bool isGoogles = 0;
bool testcase = 0;
void achilles() {
  string s;
  cin >> s;
  vector<char> sta;
  long long h = 0;
  long long n = s.size();
  for (long long i = 0; i < n; i++) {
    if (s[i] >= 'a' && s[i] <= 'z') {
      if (s[i - 1] == '/') {
        h--;
        for (long long i = 0; i < 2 * h; i++) cout << ' ';
        cout << "</" << s[i] << ">\n";
      } else {
        for (long long i = 0; i < 2 * h; i++) cout << ' ';
        cout << "<" << s[i] << ">\n";
        h++;
      }
    }
  }
}
int main() {
  ios ::sync_with_stdio(0);
  cin.tie(0);
  long long t = 1, w = 1;
  if (testcase) cin >> t;
  while (t--) {
    if (isGoogles) {
      cout << "Case #" << w << ": ";
    }
    achilles();
    w++;
  }
  return 0;
}
