Charges are "similar" if they are "somewhat alike" or "hav[e] a general likeness to each other." United States v. Rivera, 546 F.3d 245,253 (2d Cir. 2008)(quoting United States v. Werner, 620 F.2d 922, 926 (2d Cir. 1980) (internal quotation marks omitted). "Rule 8(a) does not requite `too precise an identity between the ch