def min_operations(n, s):
    operations = 0
    zero_count = 0
    
    for char in s:
        if char == '0':
            zero_count += 1
        else:  # char == '1'
            zero_count -= 1
        
        # もし0の数が1の数を超えたら、その超過分だけ操作が必要
        if zero_count > 0:
            operations = max(operations, zero_count)
    
    return operations