intmain(){ read(n); for(REG int i=1;i<=n;++i) read(A[i]); if(n==1){printf("%lld\n",A[1]);return0;} if(n==2){printf("%lld\n",A[1]|A[2]);return0;} for(REG int i=1;i<=n;++i) for(REG int j=i+1;j<=n;++j) for(REG int k=j+1;k<=n;++k) Ans=max(Ans,A[i]|A[j]|A[k]); printf("%lld\n",Ans); }