#include <bits/stdc++.h>
const int inf = int(1e9);
const int mod = inf + 7;
const double PI = acos(-1.0);
using namespace std;
const int N = 1e5 + 155;
template <typename T>
inline void read(T& x) {
  x = 0;
  int f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  x *= f;
}
string toForm(char c, bool ok) {
  string ans = "";
  ans += char(60);
  if (!ok) ans += char(47);
  ans += (c);
  ans += char(62);
  return ans;
}
void solve() {
  string s;
  cin >> s;
  int cnt = 0;
  for (int i = 1; i < s.size(); i++) {
    if (s[i] != '<' && s[i] != '>' && s[i] != '/') {
      if (s[i - 1] != '/') {
        for (int i = 0; i < cnt; ++i) cout << "  ";
        cout << toForm(s[i], true);
        cout << '\n';
        cnt++;
      } else {
        for (int i = 0; i < cnt - 1; ++i) cout << "  ";
        cout << toForm(s[i], false);
        cout << '\n';
        cnt--;
      }
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) solve();
  return 0;
}
