#include<stdio.h>
#include<stdlib.h>
unsigned long i,k,c1,c2,c3;
int main()
{
    FILE*f=fopen("kfib.in","r");fscanf(f,"%lu",&k);fclose(f);
    FILE*g=fopen("kfib.out","w");
    c1=0; c2=1;
    if(k==1) fprintf(g,"%lu",c1);
    else
    if(k==2) fprintf(g,"%lu",c2);
    else
    {
        for(i=2;i<=k;i++)
        {
            c3=(c1+c2)%10;
            c1=c2; c2=c3;
        }
        fprintf(g,"%lu",c3);
    }
    fclose(g);
    return 0;
}