Grandpa Zhang deposited some yuan in the bank for two years, with an annual interest rate of 2.41%, and the interest can be withdrawn at maturity of 77.12 yuan. How much was the principal of Grandpa Zhang deposited in the bank?
张爷爷将若干元钱存入银行两年，年利率为2.41%，到期可提取利息77.12元，求张爷爷当初存入银行的本金是多少元？
<gadget id="calculator">2.41 / 100</gadget>
<output>0.0241</output>

<gadget id="calculator">77.12 / 0.0241 / 2</gadget>
<output>1_600</output>

<result>1_600</result>