The Last Supper and the Passover Chronology

There's been this longstanding problem in the gospels where there seems to be like a four day discrepancy or something about the actual celebration. In Mark 14, for example, we read that our Lord came into Jerusalem and the anointing at Bethany takes place two days before Passover. But in John 12, the same event takes place six days before Passosy. So there is a four-day discrepancy between these two accounts. And then later, when we get to the crucifixion, John says that the crucifixion takes place on the day before apparently Passovers. Whereas the other gospels describe our Lord celebrating the Passover earlier in the week,. what we think of as Holy