First Repeated Value

Difficulty: 1000 2000 ms 128 MB

implementation

Scanning left to right, print the first value that has already appeared earlier. If all values are distinct, print NONE.

Input: the first line has an integer N; the second line has N integers separated by spaces.

Output: the first repeated value, or NONE.

Constraints:

• 1 ≤ N ≤ 2000
• −10⁹ ≤ a_i ≤ 10⁹

Sample Tests

5
2 5 3 5 2

5

3
1 2 3

NONE

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