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.
#      
import collections, atexit, math, sys, bisect 

sys.setrecursionlimit(1000000)

isdebug = False
try :
    #raise ModuleNotFoundError
    import pylint
    import numpy
    def dprint(*args, **kwargs):
        #print(*args, **kwargs, file=sys.stderr)
        # in python 3.4 **kwargs is invalid???
        print(*args,  file=sys.stderr)
    dprint('debug mode')
    isdebug = True
except Exception:
    def dprint(*args, **kwargs):
        pass


def red_inout():
    inId = 0
    outId = 0
    if not isdebug:
        inId = 0
        outId = 0
    if inId>0:
        dprint('use input', inId)
        try:
            f = open('input'+ str(inId) + '.txt', 'r')
            sys.stdin = f #标准输出重定向至文件
        except Exception:
            dprint('invalid input file')
    if outId>0:
        dprint('use output', outId)
        try:
            f = open('stdout'+ str(outId) + '.txt', 'w')
            sys.stdout = f #标准输出重定向至文件
        except Exception:
            dprint('invalid output file')
            
        atexit.register(lambda :sys.stdout.close())     #idle 中不会执行 atexit

if isdebug and len(sys.argv) == 1:
    red_inout()

def getIntList():
    return list(map(int, input().split()))            

def solve(): 
    pass
    
T_ = 1    
#T_, = getIntList()

for iii_ in range(T_):
    #solve()
    N,  = getIntList()
    #print(N)
    s = input()
    r = 0
    for i in range(N):
        if ord(s[i])%2==0:
            r+= i+1
    print(r)
