#include<stdio.h>

#define uc(x) (x%10)

int main()
{
 freopen("koba.in","r",stdin);
 freopen("koba.out","w",stdout);
 long i,t1,t2,t3,t4,s,n;
 scanf("%ld%ld%ld%ld",&n,&t1,&t2,&t3);
 t1=uc(t1); t2=uc(t2); t3=uc(t3);
 s=t1+t2+t3;
 for(i=1; i<=n-3; i++)
 {
  t4=uc(uc(uc(t3)+uc(t2*t1)));
  s+=t4;
  t1=uc(t2); t2=uc(t3); t3=uc(t4);
 }
 printf("%ld",s);
 return 0;
}