def min_operations(s):
    n = len(s)
    
    # 各位置での累積差分（00の数 - 11の数）
    balance = [0] * (n + 1)
    
    for i in range(1, n):
        balance[i] = balance[i-1]
        if s[i-1:i+1] == "00":
            balance[i] += 1
        elif s[i-1:i+1] == "11":
            balance[i] -= 1
    
    # 最大のアンバランスを求める
    min_balance = 0
    result = 0
    
    for b in balance:
        result = max(result, b - min_balance)
        min_balance = min(min_balance, b)
    
    return result