#include <stdio.h>
#define NR 100000005
int cifra(int n)
{
	return n%10;
}
int main()
{
	freopen("koba.in","r",stdin);
	freopen("koba.out","w",stdout);
	int n,m,p,q,a[NR],s=0,i;
	scanf("%d%d%d%d",&n,&m,&p,&q);
	a[1]=cifra(m);
	a[2]=cifra(p);
	a[3]=cifra(q);
	for (i=4; i<=n; i++)
		a[i]=cifra(cifra(a[i-1])+cifra(a[i-2]*a[i-3]));
	for (i=1; i<=n; i++)
		s+=a[i];
	printf("%d",s);
	return 0;
}