In a school, there are 3 groups of students: Group A, Group B, and Group C. Each group has a different schedule for attending a special workshop. Group A attends the workshop every 3 days, Group B every 4 days, and Group C every 6 days. If all groups attended the workshop together on the 1st of January, how many days in January will at least one group attend the workshop? Let's think step by step and output the final answer within \boxed{}.
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