class BIT :
    def __init__(self, n) :
        self.size = n
        self.bit = [0] * (n + 1)

    def add(self, i, x) :
        while i <= self.size :
            self.bit[i] += x
            i += i & -i
    def sum(self, i) :
        s = 0
        while i > 0 :
            s += self.bit[i]
            i -= i & -i
        return s
    def range_sum(self, l, r) :
        return self.sum(r) - self.sum(l-1)
s=list(input())
n=len(s)
ft=BIT(n+1)
for i in range(n):
    if s[i]=="0":
        ft.add(i+1,1)
rle=[]
rle.append([s[0],0])
for i in range(n):
    if rle[-1][0]==s[i]:
        rle[-1][-1]+=1
    else:
        rle.append([s[i],1])
ans=0
cnt=0
for i,j in rle:
    cnt+=j
    if i=="1":
        j//=2
        ans+=ft.range_sum(cnt+1,n)*j
print(ans)