PROGRAMMING:Recursive recursion

Linyx, a freshman, recently learned a new algorithm recursion. He found that this algorithm can solve some high school sequence problems. If F1 and the formula FN = a * fn-1 + B are known, finding FN is very convenient. Smart you should have learned recursion, so let's show it.
###Input format:
Input contains several lines of data, each line has four integers, N, F1, a, B.
###Output format:
Output FN. Each group of test data is displayed on different lines.
###Input example:
Here is a set of inputs. For example:
```in
1 4 1 1
1 6 2 3
2 2 1 1
```
###Output example:
The corresponding output is given here. For example:
```out
four
six
three
```







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