How to I make excel change a specific cell value based on other values?

Basically I have an attendance sheet on an excel spreadsheet, I want it to insert a value in the correct cell based on the date, the name on the attendance sheet and I want it to insert a 1 or a 2 depending on if they have paid or not.|||Assuming column A: Date, column B: Name, Column C: Paid. You will put in "yes" or "no" on the Paid column. Put in a formula on column D: "=if(C2="yes", 1, 2)".