Japan has come to an agreement with the U.S. to purchase four F-35 stealth fighter jets to the tune of ten-point-two billion yen each.

The two countries are set to sign the contract deal on June 29th, in which the Japanese Ministry of Defense agrees to import the fighter jets by the end of 2016.

The Japanese daily Keizai Shimbun reports that the cost, up 300 million yen from the initial projection of nine-point-nine billion yen, was due to raised labor fees spurred by a delay in production.

The purchase is part of the Japanese government’s plan to introduce a total of 42 F-35 fighter jets, which will replace the current F-4 fighters of the Japan Air Self-Defense Force.

Tokyo has set aside a budget of 60 billion yen for the fighter jets’ purchase.