pragma solidity =0.6.12; // a library for performing various math operations library Math { function min(uint x, uint y) internal pure returns (uint z) { z = x < y ? x : y; } // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method) function sqrt(uint y) internal pure returns (uint z) { if (y > 3) { z = y; uint x = y / 2 + 1; while (x < z) { z = x; x = (y / x + x) / 2; } } else if (y != 0) { z = 1; } } }