The answer is:
Switzerland
Because:
Campione d'Italia is an Italian exclave which is an enclave in Switzerland
Baarle-Hertog is a Belgian exclave which is an enclave in the Netherlands
Büsingen am Hochrhein is a German exclave which is an enclave in Switzerland
MadhaNahwa is an exclave of Omanthe United Arab Emirates which is an enclave in the United Arab EmiratesOman
San'kovo-Medvezh'e is a Russian exclave which is an enclave in Belarus
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