PROGRAMMING:Counting oil drums

The master worker codes the oil barrels into the trapezoidal shape as shown in the figure below. After counting the number of oil barrels and layers at the bottom, he knows how many oil barrels there are. Do you know what he does?
####Input format
>Number of bottom oil drums and layers
####Output format
>Number of oil drums
####Input sample
```in
7 4
```
####Output sample
```out
twenty-two
```







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