Even Substrings

You are given a string s=s_1s_2... s_n of length n, which only contains digits 1, 2, ..., 9.

A substring s[l ... r] of s is a string s_l s_{l + 1} s_{l + 2} … s_r. A substring s[l ... r] of s is called even if the number represented by it is even.

Find the number of even substrings of s. Note, that even if some substrings are equal as strings, but have different l and r, they are counted as different substrings.

Input

The first line contains an integer n (1 ≤ n ≤ 65000) — the length of the string s.

The second line contains a string s of length n. The string s consists only of digits 1, 2, ..., 9.

Output

Print the number of even substrings of s.

Examples

Input

4 1234

Output

6

Input

4 2244

Output

10

Note

In the first example, the [l, r] pairs corresponding to even substrings are:

• s[1 ... 2]
• s[2 ... 2]
• s[1 ... 4]
• s[2 ... 4]
• s[3 ... 4]
• s[4 ... 4]

In the second example, all 10 substrings of s are even substrings. Note, that while substrings s[1 ... 1] and s[2 ... 2] both define the substring "2", they are still counted as different substrings.

inputFormat

Input

The first line contains an integer n (1 ≤ n ≤ 65000) — the length of the string s.

The second line contains a string s of length n. The string s consists only of digits 1, 2, ..., 9.

outputFormat

Output

Print the number of even substrings of s.

Examples

Input

4 1234

Output

6

Input

4 2244

Output

10

Note

In the first example, the [l, r] pairs corresponding to even substrings are:

• s[1 ... 2]
• s[2 ... 2]
• s[1 ... 4]
• s[2 ... 4]
• s[3 ... 4]
• s[4 ... 4]

In the second example, all 10 substrings of s are even substrings. Note, that while substrings s[1 ... 1] and s[2 ... 2] both define the substring "2", they are still counted as different substrings.

样例

4
1234

6

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