#include <cstdio>
#include <cmath>
using namespace std;
FILE *f=fopen("cifra.in","r");
FILE *g=fopen("cifra.out","w");

int last(int x)
{
    return x%10;
}

int main()
{
    int n,s=0,b,e,i;
    fscanf(f,"%d",&n);
    for (i=1;i<=n;i++)
    {
        b=i%10;
        e=i;
        switch(b)
        {
            case 0:s+=0;break;
            case 1:s+=1;break;
            case 2:if(e%4!=0) s+=last(powl(2,e%4)); else s+=6;break;
            case 3:if(e%4!=0) s+=last(powl(3,e%4)); else s+=1;break;
            case 4:if(e%2!=0) s+=4; else s+=6;break;
            case 5:s+=5;break;
            case 6:s+=6;break;
            case 7:if(e%4!=0) s+=last(powl(7,e%4)); else s+=1;break;
            case 8:if(e%4!=0) s+=last(powl(8,e%4)); else s+=6;break;
            case 9:if(e%2!=0) s+=9; else s+=1;break;
        }
        s=s%10;
    }
    fprintf(g,"%d",s);
    return 0;
}