incorrect description about ecPairing

[wiasliaw]

According to eip-197:

Input: (a1, b1, a2, b2, ..., ak, bk) from (G_1 x G_2)^k

The input must always be a multiple of 6 32-byte values, but a set of inputs consists of two points: $ak \in G_1$ and $bk \in G_2$. The points of $G_2$ are in an extension field, which requires 2 32-byte values to represent a coordinate.

Therefore, a set of inputs definition should be: ax, ay, bx_a, bx_b, by_a, by_b. See encode section from eip-197.