removing text string

[Ahmed, Shakir]

I need to remove text string from the list of the numbers mentioned
below:

080829-7_A
070529-5_c
080824-7_O
070405_6_p

The output will be : 080829-7
                     070529-5
		         080824-7
                     070405-6    		                       

Any idea is highly appreciated.