#D3970. MUL
MUL
MUL
We have N gemstones labeled 1 through N.
You can perform the following operation any number of times (possibly zero).
- Select a positive integer x, and smash all the gems labeled with multiples of x.
Then, for each i, if the gem labeled i remains without getting smashed, you will receive a_i yen (the currency of Japan). However, a_i may be negative, in which case you will be charged money.
By optimally performing the operation, how much yen can you earn?
Constraints
- All input values are integers.
- 1 \leq N \leq 100
- |a_i| \leq 10^9
Input
Input is given from Standard Input in the following format:
N a_1 a_2 ... a_N
Output
Print the maximum amount of money that can be earned.
Examples
Input
6 1 2 -6 4 5 3
Output
12
Input
6 100 -100 -100 -100 100 -100
Output
200
Input
5 -1 -2 -3 -4 -5
Output
0
Input
2 -1000 100000
Output
99000
inputFormat
input values are integers.
- 1 \leq N \leq 100
- |a_i| \leq 10^9
Input
Input is given from Standard Input in the following format:
N a_1 a_2 ... a_N
outputFormat
Output
Print the maximum amount of money that can be earned.
Examples
Input
6 1 2 -6 4 5 3
Output
12
Input
6 100 -100 -100 -100 100 -100
Output
200
Input
5 -1 -2 -3 -4 -5
Output
0
Input
2 -1000 100000
Output
99000
样例
6
100 -100 -100 -100 100 -100200