#include <stdio.h>
      struct student { char nume[21];
                       int nr_matricol;
                       int cod_materie[3];
                       float medie_materie[3];
                        struct student *urm;};
        typedef struct student elem;


int main()
{
    int i,n;
    scanf("%d",&n);
    elem *cap_lista, *p,*q;
    p=(elem*)malloc(sizeof(elem));
    if(p==NULL) exit(1);
    scanf("%s",&p->nume);
    scanf("%d",&p->nr_matricol);
    scanf("%d",&p->cod_materie);
    scanf("%f",&p->medie_materie);
     p->urm=NULL;
     cap_lista=p;
     for(i=2;i<=n;i++)
     { q=(elem*)malloc(sizeof(elem));
    if(q==NULL) exit(1);
    scanf("%s",&q->nume);
    /*scanf("%d",&q->nr_matricol);
    scanf("%d",&q->cod_materie);*/
    scanf("%f",&q->medie_materie);
     q->urm=NULL;
     p->urm=q;
     p=q;
     }
     float sum=0;
      for(p=cap_lista,i+1;p!=NULL;p=p->urm,i++)
       sum=sum+p->medie_materie;
     printf("%f",sum);

    return 0;
}