#include <bits/stdc++.h>

int const N = 1234567;

int p[N], ans[N], q[N], deg[N];
std::vector<int> edges[N];


int main() {
    int n, m;
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; i++) {
        int v, u;
        scanf("%d%d", &v, &u);
        --v;
        --u;
        edges[v].push_back(u);
        deg[u]++;
    }
    int head = 0;
    int tail = 0;
    for (int i = 0; i < n; i++) if (deg[i] == 0) q[tail++] = i;
    while (head < tail) {
        int v = q[head++];
        for (int to : edges[v]) {
            --deg[to];
            if (deg[to] == 0) {
                q[tail++] = to;
            }
        }
    }
    if (head == n) {
        puts("NO");
        return 0;
    }
    int v = -1;
    for (int i = 0; i < n; i++) {
        if (deg[i] == 0) continue;
        v = i;
        for (int j : edges[i])
            p[j] = i;
    }
    for (int i = 0; i < n; i++) v = p[v];
    int u = p[v];
    int ac = 0;
    while (true) {
        ans[ac++] = u;
        if (u == v) break;
        u = p[u];
    }
    std::reverse(ans, ans + ac);
    puts("YES");
    for (int i = 0; i < ac; i++) {
        if (i > 0) putchar(' ');
        printf("%d", ans[i] + 1);
    }
    puts("");
}