unsigned keylocks(unsigned keys[], unsigned nkeys, unsigned locks[], unsigned nlocks)
{
  unsigned i, j;
  unsigned part1 = 0;
  for (i=0; i<nlocks; i++) {
    unsigned lock = locks[i];
    for (j=0; j<nkeys; j++)
      part1 += (lock & keys[j])==0;
  }
  return part1;
}