Count Number Of Clusters / Groups Of Given Number Occurs In Column

I have data in a column (G) consisting of zero and ones. I would like to count the number of clusters of the number 1 in the data. For example in the data below there are 8 ones. But instead, I need to calculate how many groups of 1s occur. So in the case below the group of 1s = 3.

In terms of what defines a group. Whenever there is a zero either before or after the occurance of a 1 constitues a group, i.e the groups are broken out by zeros.

0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
0
0