
int main()
{
    int n,k;
    scanf("%d %d",&n,&k);
    int data[n];
    int i;
    for(i=0;i<n;i=i+1){scanf("%d",&(data[i]));}
    
    int j;
    int s=0;
    for(i=0;i<n;i=i+1)
    {
        for(j=0;j<n;j=j+1)
        {
            if(i!=j && data[i]+data[j]==k){s=1;break;}
        }
    }
    
    if(s==1){printf("yes");}
    else{printf("no");}
    
    return(0);
    
}