How long did Jesus fast before his temptation by Satan?

In the book of Matthew we are told that Satan tempted Jesus after He had fasted for 40 days. This is the only time we are told verbatim that Jesus was tempted, but Jesus was often tempted I'm sure. No greater temptation faced Him than to not go to the cross (reference His experiences in the Garden of Gethsemane, Matthew 26:39). Matthew 4:1-3

Then Jesus was led by the Spirit into the desert to be tempted by the devil. After fasting forty days and forty nights, he was hungry. The tempter came to him and said, "If you are the Son of God, tell these stones to become bread."