#!/usr/bin/env python3

import random
k = 12 # 12 random starts are enough to succeed with high probability

(n, m), reduce, comb = map(int, input().split()), __import__("functools").reduce, __import__("math").comb
if not all(c == "0" for c in bin(n)[3:]) or m != (dims := len(bin(n)[3:])) * n // 2: exit(print("no"))
edges = [[] for _ in range(n + 1)]
for a, b in (map(int, input().split()) for _ in range(m)): (edges[a].append(b), edges[b].append(a))
for start in random.sample(range(1, n + 1), k=min(n, k)):
    node_number, numbers, seen, level, next_level, count = {start: 1}, {1}, {start}, [start], [], 0
    # if not all(len(edges[i]) == dims for i in range(1, n + 1)): exit(print("no"))  # This check IS necessary after all
    while level:
        for curr in level:
            for neigh in edges[curr]:
                if neigh not in seen:
                    seen.add(neigh)
                    next_level.append(neigh)
        count, level, next_level = count + 1, next_level, []
        if len(level) != comb(dims, count): exit(print("no"))
        if count == 1:
            for i, node in enumerate(level):
                node_number[node] = 2 << i
                numbers.add(2 << i)
        else:
            for node in level:
                new = reduce(lambda a, b: a | b, (node_number[neigh] for neigh in edges[node] if neigh in node_number), 0)
                if new in numbers: exit(print("no"))
                node_number[node] = new
                numbers.add(new)
print("yes")