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class Solution {
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  public int scoreOfParentheses(String s) {
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    Stack<Integer> st = new Stack<>();
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    int score = 0;
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    for (int i = 0; i < s.length(); i++) {
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      char ch = s.charAt(i);
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      if (ch == '(') {
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        st.push(score);
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        score = 0;
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      } else {
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        score = st.pop() + Math.max(2 * score, 1);
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      }
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    }
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    return score;
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  }
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}