#include <cstdio>

 int main(){

     int i,a,n,sum,ans;

     while(~scanf("%d",&n)){

         for(i=sum=;i<n;i++,sum+=a)scanf("%d",&a);

         for(i = ; i<sum; i++){

             if(sum==(+i)*i/){ans = ;break;}

             if(sum<(+i)*i/){ans = i;break;}

         }

         printf("yes\n%d\n",ans);

     }

     return ;

 }