PROGRAMMING:Exchange procedures between RMB and US dollar
According to the design idea of temperature conversion, the exchange rate program between RMB and US dollar is designed, and a two-way exchange program is compiled according to the exchange rate of 1 US dollar = 7 RMB.
###Input format:
Enter the amount of US dollar or RMB, with the currency before and the amount after, such as $20, ￥ 100. Enter one amount at a time.
###Output format:
Output the amount of US dollar or RMB calculated by exchange rate. The format is the same as that of input, and the result retains two decimal places.
###Input sample 1:
```in
$20
```
###Output sample 1:
```out
￥140.00
```
###Input sample 2:
```in
￥100
```
###Output sample 2:
```out
$14.29
```
###Input sample 3:
```in
#120
```
###Output sample 3:
```out
Input format error
```
answer：If there is no answer, please comment
###Input format:
Enter the amount of US dollar or RMB, with the currency before and the amount after, such as $20, ￥ 100. Enter one amount at a time.
###Output format:
Output the amount of US dollar or RMB calculated by exchange rate. The format is the same as that of input, and the result retains two decimal places.
###Input sample 1:
```in
$20
```
###Output sample 1:
```out
￥140.00
```
###Input sample 2:
```in
￥100
```
###Output sample 2:
```out
$14.29
```
###Input sample 3:
```in
#120
```
###Output sample 3:
```out
Input format error
```
answer：If there is no answer, please comment