Grandpa Li participated in the rural cooperative medical insurance. The clause stipulates: a deductible line is set for the inpatient medical expenses compensation of insured persons, 100 yuan for medical institutions at the township (town) level, and 70% of the part above the deductible line is compensated. In January this year, Grandpa Li suffered a fracture due to an accidental injury. He was hospitalized in Jingding Hospital for 28 days, and the medical expenses totaled 5,100 yuan. According to the terms and conditions, how much does Grandpa Li only need to pay?
李爷爷参加了农村合作医疗保险．条款规定：参保者住院医疗费补偿设起付线，乡(镇)级医疗机构为100元，在起付线以上的部分按70%补偿．今年1月份李爷爷由于意外伤害造成骨折，在镇定点医院住院治疗了28天，医疗费用共计5100元．按条款规定，李爷爷只需自付多少元？
<gadget id="calculator">5_100 - 100</gadget>
<output>5_000</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">5_000 * (7/10)</gadget>
<output>3_500</output>

<gadget id="calculator">5_100 - 3_500</gadget>
<output>1_600</output>

<result>1_600</result>