Flower Count from Sara and John's Gardens

Sara and John are both gardeners who grow different types of flowers. Sara grows roses and lilies, while John grows tulips and daisies. The following equations represent the relationship between the number of each type of flower:

Equation 1: $$S + J = 20$$ (where $S$ is the number of Sara's flowers and $J$ is the number of John's flowers).

Equation 2: $$2S + 3J = 57$$ (representing a combined count of flowers based on their types).

How many flowers does Sara grow?