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2007 (2)
The question is how many such numbers out of total...
are these two integers positive integers or any in...
There are two types, 1113 (e.g. 233356) and 1122 (e.g. 112236)
# of 1113 type: (6 choose 4) * 3
# of 1122 type: (6 choose 4) * (4 choose 2)