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class Solution {
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  public boolean checkPerfectNumber(int num) {
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    if (num == 1) return false;
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    int sum = 1;
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    for (int i = 2; i < Math.sqrt(num); i++) {
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      if (num % i == 0) {
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        sum += i + num / i;
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      }
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    }
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    if (sum == num) {
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      return true;
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    } else {
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      return false;
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    }
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  }
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}