#include<stdio.h>
int n,i,s=0;
int t1,t2,t3,aux;
int main ()
{

FILE *f=fopen("koba.in","r");
FILE *g=fopen("koba.out","w");

fscanf(f,"%d %d %d %d",&n,&t1,&t2,&t3);
s=s+t1%10+t2%10+t3%10;
for (i=4;i<=n;i++)
    {aux=(t3+t2+t1)%10;
     t1=t2;
     t2=t3;
     t3=aux;
     s=s+t[i];
     }

fprintf(g,"%d",s);

fclose(f);
fclose(g);
return 0;
}