You can perform a skin cancer self-exam in just 10 minutes, if you know what to look for. All you need to do is memorize five warning signs, called the ABCDEs of melanoma, which can help you distinguish between normal skin markings and what could be signs of a cancerous mole.

In these photos, courtesy of the Skin Cancer Foundation, the first example for each set is what doctors would probably consider normal skin. The second is an example of a something that could be a warning sign of melanoma.

RELATED: 5 Signs of Skin Cancer Other Than an Abnormal Mole

If you drew a line down the middle of a spot that could be melanoma, the two sides wouldn’t match.

RELATED: Are You Getting a Good Skin Cancer Check?

Uneven, squiggly edges can be a sign of early melanoma.

RELATED: 5 Best Ways to Protect Against Skin Cancer

Check for subtle shading differences within the mole, or colors other than brown or black, like red or blue. Benign moles are usually all one shade of brown.

RELATED: 3 Tips for Applying Sunscreen

A mole 1/4-inch across (about the size of a pencil eraser) or larger should set off red flags. It could be a sign of a cancerous mole.

RELATED: 10 Things You Don’t Know About Melanoma

Any changes—in size, shape, color, or more—can be signs of melanoma. Benign moles usually look the same over time.