#include <bits/stdc++.h>
#define NMAX 101
#define MOD 10

using namespace std;

ifstream in("cifra.in");
ofstream out("cifra.out");

int *p;
char n[NMAX];

void _generate()
{
    p[1] = 1;
    int x;
    for(int i=2;i<=NMAX-1;i++)
        {
            x = 1;
            for(int j = 1;j<=i;j++)
                x =  (x*i)%MOD;
            p[i] = (p[i-1] + x)%MOD;
        }
}

int main()
{
    in>>n;
    in.close();
    p = new int[NMAX];
    _generate();
    //
    int length = strlen(n);
    int nr;
    if(length==1)
        nr = n[length-1]-'0';
    else
        nr = (n[length-2]-'0')*10+(n[length-1]-'0');
    if(!nr)
    out<<p[100];
    else
        out<<p[nr];
    //
    delete[] p;
    return 0;
}