p03352 AtCoder Beginner Contest 097 - Exponential
You are given a positive integer X. Find the largest perfect power that is at most X. Here, a perfect power is an integer that can be represented as b^p, where b is an integer not less than 1 and p is an integer not less than 2.

Constraints

* 1 ≤ X ≤ 1000
* X is an integer.

Input

Input is given from Standard Input in the following format:


X


Output

Print the largest perfect power that is at most X.

Examples

Input

10


Output

9


Input

1


Output

1


Input

999


Output

961
```python
x=int(input())
l=[]
for b in range (1,32):
    for i in range (2,10):
        if b**i <=x:
            l.append (b**i)
print(max(l))
```