Stacy took 21 ears of corn, there are 14 ears to a bushel, so she took 21 ears / 14 ears/bushel = <<21/14=1.5>>1.5 bushels of corn.
In all, Bob gave away 8 bushels + 3 bushels + 12 bushels + 1.5 bushels = <<8+3+12+1.5=24.5>>24.5 bushels of corn.
This leaves him with 50 bushels - 24.5 bushels = <<50-24.5=25.5>>25.5 bushels of corn.
At 14 ears of corn per bushel, Bob has 25.5 bushels * 14 ears per bushel = <<25.5*14=357>>357 ears of corn.
#### 357