#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int main()
{int n=read(),m=read();if (m*2-1<=n) cout<<"YES";else cout<<"NO";return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int a[5],fa[5];
int find(int x){return fa[x]==x?x:fa[x]=find(fa[x]);}
int main()
{for (int i=1;i<=4;i++) fa[i]=i;for (int i=1;i<=3;i++){int x=read(),y=read();a[x]++,a[y]++;fa[find(x)]=find(y);}for (int i=1;i<=4;i++)if (find(i)!=find(1)) {cout<<"NO";return 0;}int cnt=0;for (int i=1;i<=4;i++){if (a[i]&1) cnt++;}if (cnt==2) cout<<"YES";else {cout<<"NO";return 0;}return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int main()
{int n=read(),a=read(),b=read();b-=a;if (b<=2) cout<<n+1;else{if (n<a) cout<<n+1;else{n-=a-1;ll ans=a;ans+=1ll*b*(n/2);if (n&1) ans++;cout<<ans;}}return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 200010
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int n,a[N],delta[N];
ll f[N][5];
//ll ans,f[N][2],s[N],g[N][2],h[N];
int main()
{n=read();for (int i=1;i<=n;i++) a[i]=read();/*for (int i=1;i<=n;i++)if (a[i]==0) delta[i]=2;else delta[i]=a[i]&1;for (int i=1;i<=n;i++) g[i][0]=g[i-1][0]+delta[i],s[i]=s[i-1]+a[i];ll u=0;for (int i=1;i<=n;i++){u=min(u,s[i]-g[i][0]);f[i][0]=g[i][0]+u;}for (int i=n;i>=1;i--) g[i][1]=g[i+1][1]+delta[i],s[i]=s[i+1]+a[i];u=0;for (int i=n;i>=1;i--){u=min(u,s[i]-g[i][1]);f[i][1]=g[i][1]+u;}for (int i=1;i<=n;i++) ans+=a[i];u=0;for (int i=1;i<=n;i++) ans=min(ans,f[i][1]+s[i-1]);for (int i=1;i<=n;i++) h[i]=h[i-1]+(a[i]&1^1);for (int i=1;i<=n+1;i++){ans=min(ans,f[i][1]+u+h[i-1]);u=min(u,f[i][0]-h[i]);}*/for (int i=1;i<=n;i++){f[i][0]=f[i-1][0];for (int j=1;j<=4;j++)f[i][j]=min(f[i][j-1],f[i-1][j]);f[i][0]+=a[i],f[i][4]+=a[i];f[i][1]+=a[i]==0?2:(a[i]&1);f[i][3]+=a[i]==0?2:(a[i]&1);f[i][2]+=a[i]&1^1;}ll ans=f[n][0];for (int i=1;i<=4;i++) ans=min(ans,f[n][i]);cout<<ans;return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 2010
#define P 998244353
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int n,a[N],u,v,s[N][2],f[N<<1][N<<1];
char S[N];
void inc(int &x,int y){x+=y;if (x>=P) x-=P;}
int main()
{scanf("%s",S+1);n=strlen(S+1);for (int i=1;i<=n;i++) a[i]=S[i]-'0';for (int i=1;i<=n;i++) u+=2-a[i],v+=a[i];for (int i=1;i<=n;i++) s[i][0]=s[i-1][0]+2-a[i],s[i][1]=s[i-1][1]+a[i];f[0][0]=1;for (int i=0;i<=u;i++)for (int j=0;j<=v;j++)if (i|j){if (s[min(n,i+j)][0]>=i&&s[min(n,i+j)][1]>=j){if (i) inc(f[i][j],f[i-1][j]);if (j) inc(f[i][j],f[i][j-1]);}}cout<<f[u][v];return 0;
}