How many submarines were in the Battle of Midway?

We know one Japanese sub was there for certain; it sunk the carrier Yorktown and destroyer Hamman with one torpedo salvo.

Japan deployed about 13 submarines for the Midway operation, including the I-168, which sank Yorktown and Hamman as mentioned above. The U.S. had 19 submarines stationed on patrol lines around Midway but they had little direct impact on the battle.