code: public G min() {
          int minCount = Integer.MAX_VALUE;
          G min = null;
          for (Map<G,Integer> m : orderAndSizeToGraphs.values()) {
              for (Map.Entry<G,Integer> e : m.entrySet()) {
                  if (e.getValue() < minCount) {
                      minCount = e.getValue();
                      min = e.getKey();
                  }
              }
          }
          return min;
      }
docs: {@inheritDoc}