1094: Summing Digits
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题目描述
For a positive integer n, let f (n) denote the sum of the digits of n when represented in base 10. It is easy to see that the sequence of numbers n, f (n), f (f (n)), f (f (f (n))),... eventually becomes a single digit number that repeats forever. Let this single digit be denoted g (n).
For example, consider n = 1234567892. Then:
f(n) = 1+2+3+4+5+6+7+8+9+2 = 47
f(f(n)) = 4 + 7 = 11
f(f(f(n))) = 1 + 1 = 2
Therefore, g(1234567892) = 2.
For example, consider n = 1234567892. Then:
f(n) = 1+2+3+4+5+6+7+8+9+2 = 47
f(f(n)) = 4 + 7 = 11
f(f(f(n))) = 1 + 1 = 2
Therefore, g(1234567892) = 2.
输入
Each line of input contains a single positive integer n at most 2,000,000,000. Input is terminated
by n = 0 which should not be processed.
输出
For each such integer, you are to output a single
line containing g(n).
样例输入 Copy
2
11
47
1234567892
0
样例输出 Copy
2
2
2
2