local n,m=io.read("n","n")
local t={}
for i=1,m do
	local a,b=io.read("n","n")
	t[a]=((t[a] or 0)+1)%2
	t[b]=((t[b] or 0)+1)%2
end
local checker=0
for i=1,n do
	checker=checker+(t[i] or 0)
end
print(checker>0 and "NO" or "YES")