if this program is useful for your research please cite:
B. V. Cherkassky, A. V. Goldberg, P. Martin, J. C. Setubal, and
J. Stolfi. Augment or Push? A computational study of Bipartite
Matching and Unit Capacity Maximum Flow Algorithms. ACM
Journal of Experimental Algorithmics, Volume 3, Article 8,
1998