
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Find the number of square units in the area of the shaded region. [asy]
size(200);
draw((0,0)--(50,0)--(50,50)--(0, 50)--cycle);
dot((50,0));dot((0,0));dot((20,0));dot((50,30));dot((50,50)); dot((30,50));dot((0,50));dot((0,20));
filldraw((0,0)--(20,0)--(50,30)--(50,50)--(30,50)--(0,20)--(0,0)--cycle, lightgray);
draw((0,0)--(80,0),EndArrow);
draw((0,0)--(-20,0),EndArrow);
draw((0,0)--(0,80),EndArrow);
draw((0,0)--(0,-20),EndArrow);
label("(0,0)",(0,0), SW, fontsize(8));
label("(20,0)",(20,0), S, fontsize(8));
label("(50,0)",(50,0), S, fontsize(8));
label("(50,30)",(50,30), E, fontsize(8));
label("(30,50)",(30,50), N, fontsize(8));
label("(0,50)",(0,50), W, fontsize(8));
label("(50,50)",(50,50), NE, fontsize(8));
label("(0,20)",(0,20), W, fontsize(8));
[/asy]

Present the answer in LaTex format: \boxed{Your answer}
user