For Android: 5,000,000 won upon contract,
5,000,000 won after 1 month, 5,000,000 won after 2 months = 15,000,000 won in total
For iPhone: 5,000,000 won upon contract,
5,000,000 won after 1 month, 5,000,000 won after 2 months = 15,000,000 won in total