Graph proving a cycle inequality I was solving some old exams from my university and I've stumbled across this one which I didn't know how tto think through, it says:
Give a graph $H$. Let $u(H)$ be the number of vertices of $H$ of degree 1. Let $C$ be a cycle in $H$. Show that $l(C) <= v(H) - u(H) $

HINT: Can a vertex of degree $1$ belong to $C$?
