Bank accounts $a,b,c$ contain values $,,,$ respectively. Concurrent transfers of certain amounts from accounts $a,b$ to $c$ are carried out by the following programs $(ra,rb$ are working variables$)$:

transfer of $200$ from account a to account $c$ :

transfer of $50$ from account $b$ to account $c$ :

if $)<mi\; id="EditorElement\_316385">(</mi><mn\; id="EditorElement\_316375">2</mn><mn\; id="EditorElement\_316376">0</mn><mn\; id="EditorElement\_316377">0</mn><mtext\; id="EditorElement\_316364"></mtext><mi\; id="EditorElement\_316365">\{</mi>$ABORT