#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  map<char, int> mp;
  mp.insert(pair<char, int>('A', 0));
  mp.insert(pair<char, int>('B', 0));
  mp.insert(pair<char, int>('C', 0));
  int i = 3;
  while (i--) {
    string s;
    cin >> s;
    if (s[1] == '>')
      mp[s[0]]++;
    else
      mp[s[2]]++;
  }
  if (mp['A'] == mp['B'] && mp['C'] == mp['B'])
    cout << "Impossible";
  else {
    if (mp['A'] == 0)
      cout << "A";
    else if (mp['B'] == 0)
      cout << "B";
    else if (mp['C'] == 0)
      cout << "C";
    if (mp['A'] == 1)
      cout << "A";
    else if (mp['B'] == 1)
      cout << "B";
    else if (mp['C'] == 1)
      cout << "C";
    if (mp['A'] == 2)
      cout << "A";
    else if (mp['B'] == 2)
      cout << "B";
    else if (mp['C'] == 2)
      cout << "C";
  }
  return 0;
}
