A school is collecting cans for a food drive. They are collecting two types of cans: small cans (worth 3 points each) and large cans (worth 5 points each). The total points collected was 30. The equation $3s+5L=30$ represents this, where $s$ is the number of small cans and $L$ is the number of large cans. If the school collected 3 large cans, how many small cans did they collect?