#include<bits/stdc++.h>
using namespace std;

#define ln  "\n"

void solve(int input)
{
	int a, b;
	cin >> a >> b;
	int r = abs(a - b);
	if (r <= 2)
	{
		cout << "Yes";
	}
	else
		cout << "No";
	return;

}


signed main()
{
	int t = 1;
	while (t--)
	{
		solve(t);
	}
	return 0;
}
#include<bits/stdc++.h>
#define ll long long int
#define pragi(a,b) for(ll i = a;i<b;i++)
#define pragj(a,b) for(ll j = a;j<b;j++)
#define pragk(a,b) for(ll k = a;k>=b;k--)
#define all(v) (v.begin(),v.end())
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define MP make_pair
#define MT make_tuple
#define F first
#define S second
#define KAKA ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
const int mod = 1e9 + 9;
 
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<bool> vb;
typedef long double ld;
typedef pair<int, int> pii;
//typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef pair<ll, ll> pll;

int main()
{
  KAKA
  ll x,y;
  cin>>x>>y;
  if((llabs)(x - y) < 3) cout<<"Yes"<<"\n";
  else cout<<"No"<<"\n";
}