#include<stdio.h>

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

int N,T1,T2,T3,Sol;

void citire(void)
{
	fscanf(f,"%d %d %d %d\n",&N,&T1,&T2,&T3);
}

void Rezolvare(void)
{
	int aux;
	
	T1 %= 10; T2 %= 10; T3 %= 10;
	
	Sol += T1 + T2 + T3;
	
	for(int i=4;i<=N;i++)
		aux = (T3 + T2*T1)%10,T1 = T2,T2 = T3,T3 = aux,Sol += aux;
}

int main()
{
	citire();
	Rezolvare();
	
	fprintf(g,"%d\n",Sol);
}