The store received 20 / 2 = <<20/2=10>>10 pallets of paper towels.
They received 20 / 4 = <<20/4=5>>5 pallets of tissues.
They received 20 / 5 = <<20/5=4>>4 pallets of paper plates.
Thus, the store received 20 - 10 - 5 - 4 = <<20-10-5-4=1>>1 pallet of paper cups.
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