Map<V,Integer> m = new HashMap();
        Queue <V> q = new LinkedList();
        int stamp = 0;
        for(V i : g.vertices()){
            if(i.equals(src)){
                m.put(i,stamp);
            }else{
                m.put(i,-1);
            }
        }
        q.add(src);
        while(!q.isEmpty()){
            V temp = q.remove();
            stamp++;
            for(V w : g.adjacentFrom(temp)){
                if(m.get(w) == -1){
                    q.add(w);
                    m.put(w,stamp);
                }else if(w.equals(dst)){
                    stamp++;
                    m.put(w, stamp);
                    break;
                }

            }
        }
        return stamp;