#include <stdio.h>

typedef struct tree {
  struct tree *p;
} tree;

tree *get_root (tree *t) {
  if (t == NULL || t->p == NULL) {
    return t;
  }
  
  t->p = get_root(t->p);
  return t->p;
}

int main () {
  int n = 0;
  int m = 0;
  int a = 0;
  int b = 0;
  
  int res = 0;
  
  tree t[400000] = {};
  int is_ok = 1;
  
  res = scanf("%d", &n);
  res = scanf("%d", &m);
  for (int i = 0; i < m; i++) {
    tree *rt1 = NULL;
    tree *rt2 = NULL;
    res = scanf("%d", &a);
    res = scanf("%d", &b);
    a--;
    b--;
    rt1 = get_root(t+a);
    rt2 = get_root(t+(b+n));
    if (rt1 != rt2) {
      rt2->p = rt1;
    }
    rt1 = get_root(t+(a+n));
    rt2 = get_root(t+b);
    if (rt1 != rt2) {
      rt2->p = rt1;
    }
  }
  
  for (int i = 0; i < n; i++) {
    tree *rt1 = get_root(t+i);
    tree *rt2 = get_root(t+(i+n));
    if (rt1 != rt2) {
      is_ok = 0;
    }
  }
  
  if (is_ok > 0) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  
  return 0;
}