Question: 中国联通2025年02月14日至2025年09月27日, 对于简单移动平均的20日线和10日线，有多少次死叉？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: SMA_n = 1 / n * \sum_{i=0}^{n-1} P_{t-i}
Data:
date,close
2025-01-10,4.78
2025-01-13,4.74
2025-01-14,4.85
2025-01-15,4.82
2025-01-16,4.85
2025-01-17,4.86
2025-01-20,4.83
2025-01-21,4.82
2025-01-22,4.8
2025-01-23,4.83
2025-01-24,4.87
2025-01-27,4.89
2025-02-05,4.99
2025-02-06,5.13
2025-02-07,5.23
2025-02-10,5.46
2025-02-11,5.48
2025-02-12,5.5
2025-02-13,5.5
2025-02-14,5.98
2025-02-17,6.51
2025-02-18,6.42
2025-02-19,6.44
2025-02-20,6.2
2025-02-21,6.82
2025-02-24,6.73
2025-02-25,6.63
2025-02-26,6.61
2025-02-27,6.38
2025-02-28,6.25
2025-03-03,6.22
2025-03-04,6.18
2025-03-05,6.26
2025-03-06,6.53
2025-03-07,6.41
2025-03-10,6.22
2025-03-11,6.21
2025-03-12,6.23
2025-03-13,6.13
2025-03-14,6.2
2025-03-17,6.15
2025-03-18,6.21
2025-03-19,5.77
2025-03-20,5.71
2025-03-21,5.7
2025-03-24,5.68
2025-03-25,5.61
2025-03-26,5.62
2025-03-27,5.59
2025-03-28,5.57
2025-03-31,5.56
2025-04-01,5.56
2025-04-02,5.58
2025-04-03,5.59
2025-04-07,5.2
2025-04-08,5.34
2025-04-09,5.46
2025-04-10,5.43
2025-04-11,5.41
2025-04-14,5.42
2025-04-15,5.41
2025-04-16,5.47
2025-04-17,5.44
2025-04-18,5.44
2025-04-21,5.44
2025-04-22,5.4
2025-04-23,5.34
2025-04-24,5.33
2025-04-25,5.32
2025-04-28,5.35
2025-04-29,5.34
2025-04-30,5.32
2025-05-06,5.48
2025-05-07,5.48
2025-05-08,5.46
2025-05-09,5.43
2025-05-12,5.48
2025-05-13,5.44
2025-05-14,5.54
2025-05-15,5.44
2025-05-16,5.38
2025-05-19,5.42
2025-05-20,5.47
2025-05-21,5.46
2025-05-22,5.43
2025-05-23,5.38
2025-05-26,5.4
2025-05-27,5.42
2025-05-28,5.33
2025-05-29,5.4
2025-05-30,5.36
2025-06-03,5.33
2025-06-04,5.34
2025-06-05,5.38
2025-06-06,5.42
2025-06-09,5.39
2025-06-10,5.31
2025-06-11,5.31
2025-06-12,5.27
2025-06-13,5.27
2025-06-16,5.27
2025-06-17,5.31
2025-06-18,5.29
2025-06-19,5.23
2025-06-20,5.25
2025-06-23,5.28
2025-06-24,5.33
2025-06-25,5.38
2025-06-26,5.35
2025-06-27,5.31
2025-06-30,5.34
2025-07-01,5.35
2025-07-02,5.33
2025-07-03,5.33
2025-07-04,5.34
2025-07-07,5.35
2025-07-08,5.38
2025-07-09,5.43
2025-07-10,5.41
2025-07-11,5.41
2025-07-14,5.43
2025-07-15,5.44
2025-07-16,5.42
2025-07-17,5.38
2025-07-18,5.45
2025-07-21,5.48
2025-07-22,5.49
2025-07-23,5.5
2025-07-24,5.53
2025-07-25,5.47
2025-07-28,5.43
2025-07-29,5.44
2025-07-30,5.42
2025-07-31,5.36
2025-08-01,5.32
2025-08-04,5.32
2025-08-05,5.38
2025-08-06,5.34
2025-08-07,5.35
2025-08-08,5.37
2025-08-11,5.36
2025-08-12,5.39
2025-08-13,5.44
2025-08-14,5.38
2025-08-15,5.4
2025-08-18,5.52
2025-08-19,5.47
2025-08-20,5.51
2025-08-21,5.66
2025-08-22,5.89
2025-08-25,5.82
2025-08-26,5.79
2025-08-27,5.65
2025-08-28,5.77
2025-08-29,5.7
2025-09-01,5.7
2025-09-02,5.61
2025-09-03,5.49
2025-09-04,5.39
2025-09-05,5.39
2025-09-08,5.65
2025-09-09,5.47
2025-09-10,5.76
2025-09-11,5.77
2025-09-12,5.68
2025-09-15,5.58
2025-09-16,5.58
2025-09-17,5.62
2025-09-18,5.47
2025-09-19,5.42
2025-09-22,5.47
2025-09-23,5.42
2025-09-24,5.48
2025-09-25,5.45
2025-09-26,5.41

Indicator data:
date,20日,10日
2025-02-14,5.0605,5.303
2025-02-17,5.147,5.467
2025-02-18,5.231,5.62
2025-02-19,5.310499999999999,5.765000000000001
2025-02-20,5.3795,5.872
2025-02-21,5.478,6.031000000000001
2025-02-24,5.5714999999999995,6.158
2025-02-25,5.6615,6.273
2025-02-26,5.751,6.3839999999999995
2025-02-27,5.83,6.4719999999999995
2025-02-28,5.901,6.4990000000000006
2025-03-03,5.968500000000001,6.470000000000001
2025-03-04,6.033,6.446000000000001
2025-03-05,6.0965,6.428
2025-03-06,6.1665,6.461
2025-03-07,6.225499999999999,6.42
2025-03-10,6.2635,6.369
2025-03-11,6.3,6.327
2025-03-12,6.3365,6.289
2025-03-13,6.368,6.264
2025-03-14,6.379,6.259
2025-03-17,6.361,6.252000000000001
2025-03-18,6.3505,6.255000000000001
2025-03-19,6.317,6.206
2025-03-20,6.2924999999999995,6.1240000000000006
2025-03-21,6.2364999999999995,6.053
2025-03-24,6.184,5.9990000000000006
2025-03-25,6.133,5.939
2025-03-26,6.0835,5.878
2025-03-27,6.044,5.824
2025-03-28,6.01,5.761000000000001
2025-03-31,5.977,5.702
2025-04-01,5.946,5.637
2025-04-02,5.912000000000001,5.618
2025-04-03,5.865,5.606
2025-04-07,5.8045,5.555999999999999
2025-04-08,5.7605,5.522
2025-04-09,5.723,5.507
2025-04-10,5.683,5.488
2025-04-11,5.647,5.47
2025-04-14,5.608,5.455
2025-04-15,5.571,5.4399999999999995
2025-04-16,5.534,5.431
2025-04-17,5.5175,5.417
2025-04-18,5.504,5.401999999999999
2025-04-21,5.4910000000000005,5.426
2025-04-22,5.476999999999999,5.432
2025-04-23,5.4635,5.42
2025-04-24,5.449,5.41
2025-04-25,5.4355,5.401000000000001
2025-04-28,5.4245,5.394
2025-04-29,5.4135,5.3870000000000005
2025-04-30,5.4015,5.372000000000001
2025-05-06,5.3965,5.3759999999999994
2025-05-07,5.391,5.380000000000001
2025-05-08,5.404,5.382
2025-05-09,5.4085,5.385
2025-05-12,5.4095,5.399
2025-05-13,5.41,5.41
2025-05-14,5.4165,5.432
2025-05-15,5.4175,5.441000000000001
2025-05-16,5.416,5.445
2025-05-19,5.413500000000001,5.455
2025-05-20,5.415000000000001,5.454000000000001
2025-05-21,5.4159999999999995,5.452
2025-05-22,5.4155,5.449
2025-05-23,5.4145,5.444
2025-05-26,5.4175,5.436
2025-05-27,5.422000000000001,5.433999999999999
2025-05-28,5.4225,5.412999999999999
2025-05-29,5.425,5.409000000000001
2025-05-30,5.426,5.407
2025-06-03,5.4265,5.398000000000001
2025-06-04,5.4195,5.385
2025-06-05,5.4145,5.377000000000001
2025-06-06,5.4125,5.376
2025-06-09,5.4105,5.377000000000001
2025-06-10,5.401999999999999,5.368
2025-06-11,5.3955,5.357
2025-06-12,5.382,5.351000000000001
2025-06-13,5.3735,5.337999999999999
2025-06-16,5.368,5.328999999999999
2025-06-17,5.3625,5.327
2025-06-18,5.3534999999999995,5.321999999999999
2025-06-19,5.3420000000000005,5.307
2025-06-20,5.333,5.29
2025-06-23,5.328,5.279
2025-06-24,5.3245,5.281000000000001
2025-06-25,5.3225,5.287999999999999
2025-06-26,5.3235,5.296
2025-06-27,5.319,5.3
2025-06-30,5.318,5.307
2025-07-01,5.319000000000001,5.311
2025-07-02,5.3185,5.3149999999999995
2025-07-03,5.316,5.325
2025-07-04,5.312,5.334
2025-07-07,5.3100000000000005,5.340999999999999
2025-07-08,5.3134999999999994,5.345999999999999
2025-07-09,5.3195,5.351000000000001
2025-07-10,5.3265,5.357
2025-07-11,5.333499999999999,5.367
2025-07-14,5.3415,5.376
2025-07-15,5.348,5.385
2025-07-16,5.3545,5.394
2025-07-17,5.362,5.398999999999999
2025-07-18,5.372,5.41
2025-07-21,5.382,5.423
2025-07-22,5.39,5.433999999999999
2025-07-23,5.396,5.441
2025-07-24,5.404999999999999,5.453
2025-07-25,5.413,5.4590000000000005
2025-07-28,5.4175,5.459
2025-07-29,5.422,5.4590000000000005
2025-07-30,5.4265,5.459
2025-07-31,5.428,5.457
2025-08-01,5.427,5.444
2025-08-04,5.4255,5.428
2025-08-05,5.4255,5.417
2025-08-06,5.421,5.401000000000001
2025-08-07,5.418,5.383
2025-08-08,5.416,5.373
2025-08-11,5.4125,5.3660000000000005
2025-08-12,5.41,5.361
2025-08-13,5.411,5.363
2025-08-14,5.411,5.365
2025-08-15,5.4085,5.373
2025-08-18,5.4105,5.393
2025-08-19,5.4094999999999995,5.401999999999999
2025-08-20,5.41,5.419
2025-08-21,5.4165,5.45
2025-08-22,5.4375,5.502
2025-08-25,5.457,5.548
2025-08-26,5.4745,5.587999999999999
2025-08-27,5.486,5.609
2025-08-28,5.5065,5.648
2025-08-29,5.5255,5.678
2025-09-01,5.5445,5.696
2025-09-02,5.556,5.709999999999999
2025-09-03,5.5634999999999994,5.708
2025-09-04,5.5655,5.681
2025-09-05,5.5665,5.631
2025-09-08,5.581,5.614
2025-09-09,5.585,5.582
2025-09-10,5.601,5.593000000000001
2025-09-11,5.6205,5.593
2025-09-12,5.6345,5.590999999999999
2025-09-15,5.6375,5.579
2025-09-16,5.643,5.5760000000000005
2025-09-17,5.6485,5.589
2025-09-18,5.639,5.5969999999999995
2025-09-19,5.6155,5.6
2025-09-22,5.598,5.582
2025-09-23,5.5795,5.577
2025-09-24,5.571,5.549
2025-09-25,5.555,5.517
2025-09-26,5.5405,5.49

Answer: 4.0