Graph Algorithms · Medium problem

A project has tasks $s,t,u,v,w,x$ with durations (days) and prerequisites $s \to t$ ($4$), $s \to u$ ($2$), $t \to v$ ($3$), $u \to v$ ($5$), $u \to w$ ($6$), $v \to x$ ($4$), $w \to x$ ($2$). Each listed number is how many days that task itself takes, and a task can only start once ALL of its prerequisites are finished. What is the earliest the whole project (ending at $x$) can finish, counting from day $0$?