import fileinput
from functools import cache
neginf = -1e13
@cache
def joltage(line, n):
if n == 0:
return 0
if n > len(line)-1:
return neginf
j = 0
for i in range(len(line)-1):
j = max(j, int(line[i])*10**(n-1)+joltage(line[i+1:],n-1))
return j
with fileinput.input() as lines:
print(sum(joltage(line, 12) for line in lines))