Problem C - Contiguous Sums
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You are given a sequence of N numbers, 0 <= N <= 1000000. Your task is to find
the value of the sum of a contiguous subsequence of the given numbers such that
this is the maximum of any contiguous subsequence of the given sequence.

Input
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Input consists of multiple lines, one line per case.  Each line contains
a single positive integer N followed by N integers. The input is terminated
by a line containing 0.

Output
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For each case, print one line containing the value you computed.
You should not print an output for the last line (with only a 0).

Sample Input
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12 1 1 1 1 -1 1 1 1 -1 1 -1 1
12 1 -1 1 -1 1 -1 1 1 -1 1 -1 1
10 6 -5 -4 -3 -2 -1 0 2 2 3
0

Output for Sample Input
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6
2
7