public class Main {
 
    public static void main(String[] args) {
        String S = "10101010";
 
        StringBuilder result = new StringBuilder();
        int count = 0;
 
        int i = 0;
        while (i < S.length() - 1) {
            // Check for "01"
            if (S.charAt(i) == '0' && S.charAt(i + 1) == '1') {
                result.append("10");
                count++;
                i += 2; // skip next character
            } else {
                result.append(S.charAt(i));
                i++;
            }
        }
 
        // Append last character if not processed
        if (i < S.length()) {
            result.append(S.charAt(i));
        }
 
        System.out.println("Modified String: " + result);
        System.out.println("Replacement Count: " + count);
    }
}

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