from decimal import Decimal as D for f in [3e-178, 1e-320, 3e-320, "1e-325", "3e-325"]: print("%s\t%s" % (f, D(f).log10()))
Standard input is empty
3e-178 -177.5228787452803375835172220 1e-320 -320.0000048349480421542963792 3e-320 -319.5228835802283797170013513 1e-325 -325 3e-325 -324.5228787452803375627049721