Micah had to buy 6*2=<<6*2=12>>12 stamps for 6 envelopes less than 5 pounds.
He has 52-12=<<52-12=40>>40 more stamps to buy.
There are 40/5=<<40/5=8>>8 envelopes that weigh more than 5 pounds.
Micah needed to buy 8+6=<<8+6=14>>14 envelopes.
#### 14