A tennis player computes her win ratio by dividing the number of matches she has won by the total number of matches she has played. At the start of a weekend, her win ratio is exactly \(.500\). During the weekend, she plays four matches, winning three and losing one. At the end of the weekend, her win ratio is greater than \(.503\). What's the largest number of matches she could've won before the weekend began?

(第一十届AIME1992 第3题)