num=list(map(int,input().split(',')))

def hz(nums)->int:
    n=len(nums)
    # if n==1:
    #     return nums[0]
    dp=[0]*n
    dp[0]=nums[0]
    for i in range(1,n):
        dp[i]=max(dp[i-1]+nums[i],nums[i])
    x=max(dp)
    if x>0:
        return x
    else:
        return 0

print(hz(num))