#include<stdio.h>
using namespace std;

int main()
{
	long i,t1,t2,t3,t;
	long long n=0,s=0;
FILE *f=fopen("koba.in","r"), *g=fopen("koba.out","w");
fscanf(f,"%lld%ld%ld%ld",&n,&t1,&t2,&t3);

s+=t1%10;
s+=t2%10;
s+=t3%10;
for(i=4;i<=n;i++)
	{t=(t3+t2*t1)%10;
	s+=t;
	t1=t2; t2=t3; t3=t;}
fprintf(g,"%lld\n",s);

fclose(f);
fclose(g);

return 0;}