Running sum

I have vector X of length N that I want to have a running sum for (called Y). 
I just need max(Y).  I do this with a "for" loop like so:

   Y <- vector(length=N)
   Y[1] <- X[1]
   for (i in 2:N) {
     Y[i] <- Y[i-1]+X[i]
   }
   return(max(Y))

Is there a faster way to do this?