index.js

function process(uint256[2] memory a, uint256[2][2] memory b, uint256[2] memory c, uint256[1] memory publicSignals) public {
    require(isAnswer(publicSignals[0]), "incorrect answer");
    require(verifier.verifyProof(a, b, c, publicSignals), "invalid");

    _setGreeting("answer to the ultimate question of life, the universe, and everything");
}