String1:
gtgggtgtgaattgaaagtctaacacgtgtttctctgtttatggacntggatacccacgc

String2:
gtgggtgtgaatcgaaagtctaacacgtgtttctctgtttatggacntgtttacccacgc

random:
TTGGGTAACTTTACATCGCAATGACGTCGTACCGCGCGATATGATCCCTGTGTGAACCAA

The E value for an alignment score "S" represents the number of hits with a 
score equal to or better than "S" that would be "expected" 
by chance (the background noise) when searching a database of a particular size.