30 beads are strung together in a circle in the order of 8 red beads, 2 black beads, 8 red beads, and 2 black beads. A grasshopper jumps from the second black bead, skips 6 beads each time and lands on the next bead. The grasshopper must jump at least how many times before it lands on the black bead.
30粒珠子依8粒红色、2粒黑色、8粒红色、2粒黑色、…的次序串成一圈．一只蚱蜢从第2粒黑珠子起跳，每次跳过6粒珠子落在下一粒珠子上．这只蚱蜢至少要跳多少次才能落在黑珠子上．
<result>7</result>