Background

The fairy was short of money because he had just arrived in the world, so he went to the bank for a loan.

神仙由于刚到凡间故手上缺钱，于是他去银行贷款了。

Description

Therefore, he will have to repay the fixed installment every month for a period of time after the loan. This problem requires the calculation of the interest rate paid by the fairy to the bank. Suppose the interest rate is accumulated on a monthly basis.

因此，他在贷款之后，在一段时间内将不得不每月偿还固定的分期付款。这个问题要求计算神仙向银行支付的利率。假设利率按月累计。

Format

Input

Enter only one line containing three positive integers separated by spaces. The first integer represents the original value of the loan, the second integer represents the monthly installment amount, and the third integer represents the total number of months required to repay the loan by installment.

输入仅一行包含三个用空格隔开的正整数。 第一个整数表示贷款的原值，第二个整数表示每月支付的分期付款金额，第三个整数表示分期付款还清贷款所需的总月数。

Output

Output a real number that represents the monthly interest rate of the loan (expressed as a percentage), rounded to the nearest 0.1%.

输出一个实数，表示该贷款的月利率(用百分数表示)，四舍五入精确到0.1%。

Sample 1

Input

1000 100 12

Output

2.9

Limitation

（无）

Source

Amorphophallus Orz Group