#include<iostream> 
#include<fstream> 
using namespace std; 
int a[10000],b[10000]; 
int main () 
{ int n,i,k=1,max,max1; 
  
ifstream fin("subsir2.in"); 
  
ofstream fout("subsir2.out"); 
  
fin>>n; 
  
for(i=1;i<=n;i++) 
  
{ 
      
fin>>a[i]; 
  
} 
  
max=-1000000; 
  
max1=1; 
  
b[max1]=a[1]; 
  
while(max!=1000000) 
  
{ 
      
max++; 
      
for(i=2;i<=n;i++) 
      
{ 
          
if((a[i]==max)&&(i>max1)) 
          
{ 
              
max1=i; 
              
k++; 
              
b[k]=a[i]; 
          
} 
          
if(i==n) break; 
      
} 
  
} 
  
fout<<k<<endl; 
  
for(i=1;i<=k;i++) 
  
{ 
      
fout<<b[i]<<" "; 
  
} 
  
fin.close(); 
  
fout.close(); 
  
return 0; 
}