两个不平稳的序列经过一阶差分之后变成平稳序列，现在想要建立这两个序列之间的关系，该怎么建模呢？比如沪深两市的月平均收盘价？
数据如下：
96.99000  378.7400
40.98000  109.2900
-0.730000  164.7600
141.9200  331.7000
201.0800  444.0000
30.91000  9.560000
-59.48000 -354.7600
45.91000  231.9400
93.78000  147.9400
85.57000  295.2000
261.3000  1045.020
576.1800  980.1400
110.8700  985.8000
94.73000  406.7600
302.9100  509.5000
657.2900  2316.680
268.3800  2078.350
-288.9500 -397.7800
650.3300  2653.110
747.8000  2672.550
333.4700  992.4400
402.4700  666.6000
-1082.990 -3893.490
389.7800  2062.960
-878.1700 -1842.910
-34.85000 -33.83000
-875.8300 -2521.740
220.4000  202.7400
-259.7600 -1456.640
-697.2500 -2677.460
39.62000  99.55000
-378.3500 -1466.090
-103.5900 -444.9700
-564.9900 -1719.940
142.3700  819.1800
-50.35000 -173.0000
169.8500  529.7300
92.19000  592.9800
290.3600  1373.730
104.3600  520.5700
155.3600  625.4000
326.4300  1438.690
452.7000  2104.110
-744.3100 -3085.640
111.6800  621.7700
216.4200  1090.310
199.4500  1189.610
81.84000  213.2000
-287.8500 -1562.770
62.65000  299.4600
57.17000  57.69000
-238.5000 -1331.810