3
PERLIS SELL A 300
WILKES BUY A 200
HAMMING SELL A 100
4
BACKUS SELL A 10
FLOYD BUY A 20
IVERSON SELL B 30
BACKUS BUY B 40
7
WILKINSON SELL A 500
MCCARTHY BUY C 300
WILKINSON SELL C 200
DIJKSTRA SELL B 100
BACHMAN BUY A 400
DIJKSTRA BUY A 600
WILKINSON SELL A 300
2
ABCD SELL X 10
ABC BUY X 15
2
A SELL M 100
A BUY M 100
0