#include <bits/stdc++.h>
using namespace std;
char s[1005];
int main() {
  scanf("%s", s);
  int n = strlen(s);
  int t = 0;
  for (int i = 0; i < n; i++) {
    int x = 1;
    if (s[i + 1] == '/') x = -1;
    t += x;
    for (int j = 0; j < t - (x == 1); j++) printf("  ");
    for (int j = i; j < i + 3 + (x == -1); j++) printf("%c", s[j]);
    puts("");
    i += 2 + (x == -1);
  }
  return 0;
}
