sample = "2333133121414131402"
input = open("input").read().strip()

def expand(s):
    disk = []
    id = 0
    for i in range(len(s)):
        d = int(s[i])
        if i % 2 == 0:
            disk.extend([id]*d)
            id += 1
        else:
            disk.extend([-1] * d) # free space
    return disk

def solve(input):
    disk = expand(input)
    if len(disk) < 100:
        print(disk)
    while disk[-1] == -1:
        disk.pop()
    free = 0
    last = len(disk)-1
    while free < last:
        while disk[free] != -1:
            free += 1
        if free >= last:
            break
        disk[free] = disk[last]
        disk[last] = -1
        while free < last and disk[last] == -1:
            last -= 1

        if len(disk) < 100:
            print(free, last, disk)
    t = 0
    for i, x in enumerate(disk):
        if x == -1:
            continue
        t += i*x
    print(t)


solve(sample)
solve(input)