#include<iostream>
using namespace std;

int main(){
  int n,m;
  cin>>n>>m;
  int d;
  if(n>=m) d=n-m;
  else d=m-n;
  if(d>=3) cout<<"No"<<endl;
  else cout<<"Yes"<<endl;
}
  
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define mem0(a) memset(a,0,sizeof(a))
#define mem1(a) memset(a,-1,sizeof(a))
#define memf(a) memset(a,false,sizeof(a))
#define all(v) (v).begin(),(v).end()
#define lb lower_bound
#define ub upper_bound
#define pll pair<ll,ll>
#define mll map<ll,ll>
#define endl "\n"
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define DEC(x) fixed<<setprecision(x)
#define FAST ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
#define gcd(a,b) __gcd((a),(b))
#define lcm(a,b) ((a)*(b))/__gcd((a),(b))
const int M=1000000007;
const int MM=998244353;
const long double PI = acos(-1);
const long long INF=2e18;

template<typename T,typename T1>void amax(T &a,T1 b){if(b>a)a=b;}
template<typename T,typename T1>void amin(T &a,T1 b){if(b<a)a=b;}

ll power( ll b, ll e)
{
    if(e==0) return 1;
    if(e&1) return b*power(b*b,e/2);
    return power(b*b,e/2);
}
ll power(ll b,ll e,ll m)
{
    if(e==0) return 1;
    if(e&1) return b*power(b*b%m,e/2,m)%m;
    return power(b*b%m,e/2,m);
}
ll modinv(ll a,ll m)
{
    return power(a,m-2,m);
}

// #define _NCR_

int TLE_TERROR()
{
 	ll a,b;
 	cin>>a>>b;
 	ll n=abs(a-b);
 	if(n<3)
 		cout<<"Yes"<<endl;
 	else 
 		cout<<"No"<<endl;
 	
 	return 0;   
}

int main()
{
    FAST
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    ll int TESTS=1;
    // cin>>TESTS;
    #ifdef _NCR_
        initialvalues();
    #endif
    while(TESTS--)
        TLE_TERROR();
    return 0;
}