All Elements Even Frequency

Given an array of integers, determine whether every distinct element in the array appears an even number of times. In other words, for every integer x in the array, its frequency should satisfy the equation: $$frequency(x) \mod 2 = 0$$. If this condition is met for every element, output True, otherwise output False.

Examples:

• Input: [2, 4, 2, 4] → Output: True
• Input: [3, 3, 4, 4, 4] → Output: False
• Input: [] → Output: True

You need to read input from standard input and write the result to standard output.

inputFormat

The first line of input contains a single integer n (0 ≤ n ≤ 10⁶), which indicates the number of elements in the array. The second line contains n space-separated integers representing the array.

outputFormat

Output a single line: True if every element in the given array occurs an even number of times, otherwise output False.

4
2 4 2 4

True