#!/usr/local/bin/python3 def rk(m,n): m=list(m);r=0 for c in range(n): b=1<>n for i in range(n)] t=6 U=[[0,1,0,0,0,1],[0,0,1,0,0,1],[0,0,0,1,0,1],[0,0,0,0,1,1]] c=0 for mask in range(1<<15): W=[0]*t;k=0 for i in range(t): for j in range(i+1,t): if (mask>>k)&1:W[i]|=1<>j)&1):v^=1 if v:row|=1<