import sys
sys.setrecursionlimit(10**6)


n, m = map(int, input().split())
g = [[] for i in range(n)]
for i in range(m):
    a, b = map(int, input().split())
    if (b - 1 not in g[a - 1]):
        g[a - 1].append(b - 1)
'''
n = int(input())
g = [list(map(int, input().split())) for i in range(n)]
'''
used = [0] * n
cnt = 0
E = []


def dfs(v):
    used[v] = 1
    fl = False
    for i in g[v]:
        if (not used[i]):
            if (dfs(i)):
                fl = True
        else:
            if (used[i] == 1):
                fl = True
    used[v] = 2
    E.append(v + 1)
    return fl


fl = False
for i in range(n):
    if (not used[i]):
        if (dfs(i)):
            fl = True
if (not fl):
    print("YES")
    for i in range(n - 1, -1, -1):
        print(E[i], end = ' ')
else:
    print("NO")