                   person                   knows
0  ZMjJcoGhNLdZg3CSjXkjTw  v3PMBEmnWi5E2MxI4bGfzQ
1  arwQnxvlM5toxMXT17fYbQ  ZMjJcoGhNLdZg3CSjXkjTw
2  v3PMBEmnWi5E2MxI4bGfzQ  arwQnxvlM5toxMXT17fYbQ