Blake Haddon, Cyrus Oldsmen, and Graham Piper work for Aragon Foods. They work long hours for which they have quite a bit of overtime. In the initial employment contract, which is in writing, the contract stated that each person would be paid an hourly rate of $15.00 and anything over 40 hours would be paid at time and a half. During the first two years of the contract, there were times when Blake, Cyrus, and Graham were not paid their overtime. However, two years after they all had started, Aragon Foods had each of the employees sign a new employment contract where they would work for a salary of $40,000. The contract expressly stated that they did not get overtime. Blake, Cyrus, and Graham want to sue for the overtime that they were never paid. What effect does the new contract have, if any, on the first employment agreement