Chemical Equation Balancer

This balancer reads each formula into its atom counts, then solves the conservation equations exactly with fractions instead of floating point, so the coefficients it prints are the true smallest whole numbers. Write the reaction with a plus sign between formulas and = or -> between the two sides; brackets, nested brackets and hydrates written as CuSO4*5H2O are understood, and any coefficient you have already typed is dropped and worked out again. It handles neutral molecular equations only, so charges, ionic half equations, electrons and state symbols are refused with a message. When an equation has no balance in positive whole numbers, or has more than one independent balance, it says so rather than printing something wrong.