
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
In the 2008 Olympic Games, there were 7 volunteers, including 4 males and 3 females. Two volunteers are randomly selected to guide tourists. Among the following events:  
① Exactly 1 female and exactly 2 females;  
② At least 1 female and all females;  
③ At least 1 male and at least 1 female;  
④ At least 1 female and all males.  
The number of pairs of mutually exclusive events is ______.

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