Graph Algorithms · Easy problem

A project has tasks $s,t,u,v$ with durations (days) and prerequisites $s \to t$ ($3$ days), $s \to u$ ($2$ days), $t \to v$ ($4$ days), $u \to v$ ($5$ days). Task $v$ can only start once ALL of its prerequisite tasks are finished. What is the earliest day $v$ can be completed, counting from day $0$?