int main()
{
Trie trie;
DisjointSet djset;
int degree[500001] = {0};
string word1, word2;
char w1[15], w2[15];
int hash1, hash2;
while (scanf("%s %s", w1, w2) != EOF) {
hash1 = trie.addWord(w1);
hash2 = trie.addWord(w2);
degree[hash1]++;
degree[hash2]++;
djset.union_set(hash1, hash2);
}
int max_count = trie.max_count();
int sum = 0;
for (int i = 0; i < max_count; i++) {
if (degree[i] & 1)
sum++;
if (sum > 2) {
cout << "Impossible" << endl;
return 0;
}
}
for (int i = 0; i < max_count; i++) {
if (djset.find_set(i) != djset.find_set(0)) {
cout << "Impossible" << endl;
return 0;
}
}
cout << "Possible" << endl;
return 0;
}
inline bool
same_component(Vertex u, Vertex v, DisjointSet& ds) {
return ds.find_set(u) == ds.find_set(v);
}