In the parable of the Pharisee and the tax collector, what did the tax collector pray?

Answer: God, have mercy on me, a sinner

Beating his breast, he prayed, "God, have mercy on me, a sinner!" He, not the Pharisee, went home justified.

“But the tax collector stood at a distance, unwilling even to lift up his eyes to heaven. Instead, he beat his breast and said, ‘God, have mercy on me, a sinner!’ I tell you, this man, rather than the Pharisee, went home justified. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.””— Luke 18:13-14 (BSB)