Question: 2021年12月02日-2022年04月18日，华润微加权移动平均线中20日均线和30日均线金叉的次数是多少？（权重取 1, 2, ..., n）使用不复权价格，写出指标公式，搜集原始数据，计算得出答案，保留四位小数。注意列出原始数据和关键计算过程。
Formula: WMA_n = \sum_{i=0}^{n-1} (n-i) * P_{t-i} / \sum_{j=1}^{n} j
Data:
date,close
2021-10-22,69.07
2021-10-25,68.95
2021-10-26,70.02
2021-10-27,62.14
2021-10-28,60.06
2021-10-29,61.78
2021-11-01,62.6
2021-11-02,64.78
2021-11-03,64.92
2021-11-04,67.66
2021-11-05,66.94
2021-11-08,66.33
2021-11-09,67.72
2021-11-10,68.09
2021-11-11,69.68
2021-11-12,65.41
2021-11-15,65.75
2021-11-16,65.37
2021-11-17,66.52
2021-11-18,64.5
2021-11-19,65.2
2021-11-22,69.95
2021-11-23,72.74
2021-11-24,73.01
2021-11-25,73.33
2021-11-26,72.6
2021-11-29,71.42
2021-11-30,71.58
2021-12-01,71.68
2021-12-02,70.8
2021-12-03,73.2
2021-12-06,69.66
2021-12-07,67.5
2021-12-08,68.54
2021-12-09,72.49
2021-12-10,71.1
2021-12-13,69.93
2021-12-14,69.92
2021-12-15,67.7
2021-12-16,67.39
2021-12-17,64.55
2021-12-20,63.01
2021-12-21,64.16
2021-12-22,64.23
2021-12-23,64.54
2021-12-24,63.16
2021-12-27,63.92
2021-12-28,64.64
2021-12-29,63.63
2021-12-30,64.55
2021-12-31,64.6
2022-01-04,63.13
2022-01-05,61.0
2022-01-06,61.32
2022-01-07,61.24
2022-01-10,61.9
2022-01-11,60.45
2022-01-12,61.33
2022-01-13,60.4
2022-01-14,60.7
2022-01-17,61.28
2022-01-18,62.18
2022-01-19,61.04
2022-01-20,58.26
2022-01-21,58.65
2022-01-24,59.21
2022-01-25,56.99
2022-01-26,57.47
2022-01-27,55.12
2022-01-28,54.69
2022-02-07,55.41
2022-02-08,55.54
2022-02-09,56.26
2022-02-10,57.1
2022-02-11,56.46
2022-02-14,55.39
2022-02-15,57.1
2022-02-16,56.71
2022-02-17,56.45
2022-02-18,54.92
2022-02-21,54.2
2022-02-22,54.83
2022-02-23,58.26
2022-02-24,58.03
2022-02-25,58.06
2022-02-28,58.67
2022-03-01,57.8
2022-03-02,56.9
2022-03-03,56.1
2022-03-04,56.82
2022-03-07,54.69
2022-03-08,54.83
2022-03-09,55.68
2022-03-10,55.54
2022-03-11,57.78
2022-03-14,56.63
2022-03-15,54.9
2022-03-16,58.81
2022-03-17,59.1
2022-03-18,60.93
2022-03-21,61.0
2022-03-22,59.35
2022-03-23,59.8
2022-03-24,57.98
2022-03-25,57.8
2022-03-28,56.8
2022-03-29,54.74
2022-03-30,55.98
2022-03-31,54.77
2022-04-01,55.14
2022-04-06,53.48
2022-04-07,52.84
2022-04-08,52.48
2022-04-11,48.25
2022-04-12,48.6
2022-04-13,46.8
2022-04-14,48.2
2022-04-15,48.6
2022-04-18,49.7

Indicator data:
date,20日,30日
2021-12-02,70.04419047619048,68.92337634408602
2021-12-03,70.45076190476192,69.27907526881721
2021-12-06,70.49038095238095,69.3975053763441
2021-12-07,70.30842857142858,69.37505376344086
2021-12-08,70.22657142857142,69.4251182795699
2021-12-09,70.5187619047619,69.71625806451613
2021-12-10,70.66519047619047,69.89098924731182
2021-12-13,70.67309523809524,69.97019354838712
2021-12-14,70.66014285714286,70.03298924731183
2021-12-15,70.41409523809524,69.94150537634408
2021-12-16,70.13290476190475,69.82404301075267
2021-12-17,69.56747619047619,69.52393548387097
2021-12-20,68.8584761904762,69.1296129032258
2021-12-21,68.29204761904762,68.81662365591399
2021-12-22,67.77314285714287,68.5158064516129
2021-12-23,67.32557142857142,68.24329032258065
2021-12-24,66.78842857142857,67.89279569892473
2021-12-27,66.36861904761903,67.59617204301074
2021-12-28,66.05309523809524,67.34993548387096
2021-12-29,65.67442857142856,67.04010752688173
2021-12-30,65.42171428571429,66.79584946236558
2021-12-31,65.20352380952382,66.55470967741935
2022-01-04,64.88628571428572,66.22002150537635
2022-01-05,64.3972857142857,65.7625806451613
2022-01-06,63.96971428571429,65.35103225806452
2022-01-07,63.56890476190476,64.95946236559139
2022-01-10,63.28452380952381,64.63647311827957
2022-01-11,62.90585714285715,64.24294623655915
2022-01-12,62.65614285714286,63.929784946236566
2022-01-13,62.358761904761906,63.57866666666666
2022-01-14,62.12471428571429,63.27116129032259
2022-01-17,61.97776190476191,63.02279569892474
2022-01-18,61.932095238095236,62.85812903225806
2022-01-19,61.781809523809514,62.63600000000001
2022-01-20,61.381619047619054,62.24840860215054
2022-01-21,61.047,61.908086021505376
2022-01-24,60.79376190476191,61.63365591397849
2022-01-25,60.34790476190476,61.24156989247312
2022-01-26,59.98076190476189,60.908279569892464
2022-01-27,59.42395238095238,60.450150537634414
2022-01-28,58.86671428571429,59.99133333333334
2022-02-07,58.425,59.60627956989247
2022-02-08,58.039428571428566,59.24926881720431
2022-02-09,57.75857142857142,58.95477419354838
2022-02-10,57.58028571428571,58.73146236559139
2022-02-11,57.36114285714286,58.482193548387094
2022-02-14,57.062857142857126,58.181268817204305
2022-02-15,56.95842857142858,58.00737634408602
2022-02-16,56.83280952380952,57.822989247311824
2022-02-17,56.704428571428565,57.638881720430106
2022-02-18,56.44914285714285,57.37150537634409
2022-02-21,56.15280952380952,57.078387096774186
2022-02-22,55.95019047619047,56.84827956989247
2022-02-23,56.1092380952381,56.857311827956984
2022-02-24,56.25961904761905,56.85739784946238
2022-02-25,56.41395238095238,56.86649462365591
2022-02-28,56.62919047619047,56.92178494623656
2022-03-01,56.76414285714285,56.927892473118284
2022-03-02,56.80952380952381,56.88163440860214
2022-03-03,56.78142857142857,56.793290322580646
2022-03-04,56.817238095238096,56.76064516129033
2022-03-07,56.64004761904761,56.5989247311828
2022-03-08,56.47961904761905,56.460408602150544
2022-03-09,56.40352380952382,56.3925376344086
2022-03-10,56.316857142857145,56.32716129032259
2022-03-11,56.45095238095237,56.41215053763441
2022-03-14,56.46923809523809,56.42481720430108
2022-03-15,56.31685714285714,56.33141935483871
2022-03-16,56.547333333333334,56.49477419354839
2022-03-17,56.79542857142857,56.67395698924731
2022-03-18,57.205190476190474,56.96264516129033
2022-03-21,57.592999999999996,57.24243010752688
2022-03-22,57.79128571428571,57.40374193548387
2022-03-23,58.010904761904754,57.58589247311828
2022-03-24,58.04985714285714,57.64301075268818
2022-03-25,58.071904761904754,57.68662365591398
2022-03-28,57.99995238095238,57.66283870967741
2022-03-29,57.74071428571428,57.5031182795699
2022-03-30,57.61414285714285,57.42847311827958
2022-03-31,57.37671428571428,57.277333333333324
2022-04-01,57.18085714285714,57.153677419354835
2022-04-06,56.83490476190477,56.92245161290324
2022-04-07,56.43376190476191,56.65148387096774
2022-04-08,56.00780952380953,56.36156989247311
2022-04-11,55.1942380952381,55.81118279569892
2022-04-12,54.44871428571428,55.30440860215054
2022-04-13,53.57547619047618,54.701849462365594
2022-04-14,52.88238095238095,54.21513978494623
2022-04-15,52.25928571428571,53.77488172043011
2022-04-18,51.78957142857143,53.42344086021505

Answer: 3.0