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class Solution {
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  public int calculateSetBits(String s) {
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    int count = 0;
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    for (int i = 0; i < s.length(); i++) {
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      if (s.charAt(i) == '1') count++;
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    }
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    return count;
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  }
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  public boolean isPrime(int n) {
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    if (n == 0 || n == 1) return false;
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    for (int i = 2; i <= n / 2; i++) {
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      if (n % i == 0) return false;
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    }
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    // System.out.println(n+" - ");
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    return true;
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  }
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  public int countPrimeSetBits(int left, int right) {
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    int count = 0;
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    for (int i = left; i <= right; i++) {
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      String b = Integer.toBinaryString(i);
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      int n = calculateSetBits(b);
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      if (isPrime(n)) count++;
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    }
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    return count;
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  }
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}