The curve I am using is secp256r1. Its formulae is
$y^2 == x^3 + a\cdot x + b$
$a$ = 0xffffffff00000001000000000000000000000000fffffffffffffffffffffffc (115792089210356248762697446949407573530086143415290314195533631308867097853948)
$b$ = 0x5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b (41058363725152142129326129780047268409114441015993725554835256314039467401291)
And I am checking the base point $G$:
$G_x$ = 0x6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296 (48439561293906451759052585252797914202762949526041747995844080717082404635286)
$G_y$ = 0x4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5 (36134250956749795798585127919587881956611106672985015071877198253568414405109)
Calculating left side $y^2$ gives me:
1305684092205373533040221077691077339148521389884908815529498583727542773586739078600732747106020956683600164371063053787771205051084393085089418365301881
Calculating right side $x^3 + a\cdot x + b$ gives:
113658155427813365024510503555061841058107074695539734801914243855899581676106121216742031186749037217068373713699401633275460693094202620308271598867055040123401752346577561684789671973397929725392419990583281258891711488349384075
Left and right sides are not equal.
What I am doing wrong in my calculations?