How to multiply few matrices with less complexity in C++?

Question

I mean I want to multiply few matrices in the way that the process of multiplication is the least so the time complexity would be decreased a lot,

 

for example:

matrix1[2][5]

matrix2[5][3]

matrix3[5][9]

matrix4[6][7]

matrix5[7][3]

matrix6[8][3]

matrix7[3][7]

so I want to find the best chain of multiplication for this to have the least multiplication process so please help me to implement it.