#include <stdio.h>

typedef struct Edge {
	struct Edge *next;
	int v;
} edge;

int main()
{
	int i, n, m, u, w;
	edge *adj[101] = {}, e[10001], *p;
	scanf("%d %d", &n, &m);
	for (i = 0; i < m; i++) {
		scanf("%d %d", &u, &w);
		e[i*2].v = w;
		e[i*2+1].v = u;
		e[i*2].next = adj[u];
		e[i*2+1].next = adj[w];
		adj[u] = &(e[i*2]);
		adj[w] = &(e[i*2+1]);
	}
	
	int r, color[101] = {}, q[101], head, tail;
	for (r = 1; r <= n; r++) {
		if (color[r] != 0) continue;
		color[r] = 1;
		q[0] = r;
		for (head = 0, tail = 1; head < tail; head++) {
			u = q[head];
			for (p = adj[u]; p != NULL; p = p->next) {
				w = p->v;
				if (color[w] == 0) {
					color[w] = -color[u];
					q[tail++] = w;
				} else if (color[w] == color[u]) {
					printf("No\n");
					return 0;
				}
			}
		}
	}
	printf("Yes\n");
	fflush(stdout);
	return 0;
}