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.
"""
Author    : raj1307
Institute : Jalpaiguri Government Engineering College
Date      : 21.03.19
"""
from __future__ import division, print_function
import itertools,os,sys
#from collections import deque, Counter, OrderedDict
#from heapq import nsmallest, nlargest, heapify, #heappop ,heappush, heapreplace
#from math import ceil,floor,log,sqrt,factorial,pow,pi
#from bisect import bisect_left,bisect_right
#from decimal import *
from atexit import register
from io import BytesIO, StringIO

if sys.version_info[0]<3:
    range = xrange
    filter = itertools.ifilter
    map = itertools.imap
    zip = itertools.izip
    sys.stdin = BytesIO(os.read(0, os.fstat(0).st_size))
    sys.stdout = BytesIO()
    register(lambda: os.write(1, sys.stdout.getvalue()))
else:
    sys.stdin = StringIO(os.read(0, os.fstat(0).st_size).decode())
    sys.stdout = StringIO()
    register(lambda: os.write(1, sys.stdout.getvalue().encode()))

input = lambda: sys.stdin.readline().rstrip('\r\n')

def ii(): return int(input())
def si(): return str(input())
def mi():return map(int,input().strip().split(" "))
def li():return list(mi())

abc='abcdefghijklmnopqrstuvwxyz'
abd={'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}
def getKey(item): return item[0] 
def sort2(l):return sorted(l, key=getKey)
def d2(n,num):return [[num for x in range(n)] for y in range(n)]
def ntl(n):return [int(i) for i in str(n)]
def powerMod(x,y,p):
    res = 1
    x %= p
    while y > 0:
        if y&1:
            res = (res*x)%p
        y = y>>1
        x = (x*x)%p
    return res
def gcd(x, y):
    while y:
        x, y = y, x % y
    return x

def main():
    n=ii()
    l=si()
    cnt=0
    for i in range(n):
        if int(l[i])%2==0:
            cnt+=i+1
    
    print(cnt)
   
if __name__ == "__main__":
    main()