Given the data below, the column-pair with the same values for at least 4 consecutive rows should be highlighted.

image here for better visualization: http://i49.tinypic.com/2jeshtt.jpg
2 2
3 4
3 4
3 4
3 4
2 3
1 2
2 2
3 3
3 3
3 3
3 3
2 3
2 3
2 3
2 3
2 2
3 4
3 4
3 4
3 4
3 4

The output should be something like this, where the column-pair values that are the same for at least 4 consecutive rows are highlighted.

image here for better visualization: http://i48.tinypic.com/i2lzc8.jpg
2 2
3 4
3 4
3 4
3 4
2 3
1 2
2 2
3 3
3 3
3 3
3 3
2 3
2 3
2 3
2 3
2 2
3 4
3 4
3 4
3 4
3 4

Then, I need to know the number of instances of the N-consecutive equal column-pair. Considering the data above, N=4 should be 3 and N=5 should be 1, where N is the number of rows that the column-pair is consecutively equal.