2sk241 and 2sc1815 equivalents on RF preamplifier

Hello, I am building this frequency counter (30MHz max frequency input)
../imgqa/eboard/Antenna/rf-0hvraggca0c.gif
I would like to replace the input transistors of the preamplifier with European/US transistors.
Can I use MPF102 and 2n2222 for these without changing the rest of the components?
What are the exact equivalents?

MPF102 & 2n2222 would be OK, almost any general purpose juntion FET & transistor should work.