#include<bits/stdc++.h>
using namespace std;
using lli = long long;
#define rep(i,n) for(int i=0;i<n;i++)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<class T>
ostream &operator<<(ostream &os, const vector<T> &x){
    os << "{";
    for(size_t i = 0; i < x.size(); i++){
        if(i < x.size()-1) os << x[i] << ", ";
        else os << x[i];
    }
    os << "}";
    return os;
}

template< int mod >
struct ModInt {
  int x;

  ModInt() : x(0) {}

  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

  ModInt &operator+=(const ModInt &p) {
    if((x += p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator-=(const ModInt &p) {
    if((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }

  ModInt &operator*=(const ModInt &p) {
    x = (int) (1LL * x * p.x % mod);
    return *this;
  }

  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }

  ModInt operator-() const { return ModInt(-x); }

  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

  bool operator==(const ModInt &p) const { return x == p.x; }

  bool operator!=(const ModInt &p) const { return x != p.x; }

  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while(b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }

  ModInt pow(int64_t n) const {
    ModInt ret(1), mul(x);
    while(n > 0) {
      if(n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }

  friend ostream &operator<<(ostream &os, const ModInt &p) {
    return os << p.x;
  }

  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt< mod >(t);
    return (is);
  }

  static int get_mod() { return mod; }
};
const int mod = 10;
using modint = ModInt< mod >;


int main(void){
    lli p, q, r, k;
    cin >> p >> q >> r >> k;
    int m = 20;
    vector<modint> A(2021);
    A[0] = p;
    A[1] = q;
    A[2] = r;
    k = k-3;
    int f[10][10][10];
    int L = -1, R = -1;
    rep(i, 10) rep(j, 10) rep(t, 10) f[i][j][t] = -1;
    for(int i = 3; i < 1002; i++){
        int s, t, u;
        s = A[i-1].x;
        t = A[i-2].x;
        u = A[i-3].x;
        if(f[s][t][u] > 0){
            L = f[s][t][u];
            R = i;
            break;
        }
        A[i] = A[i-1]+A[i-2]+A[i-3];
        f[s][t][u] = i;
    }
    int to = 3+R+(k-R)%(R-L);
    for(int i = R; i < to; i++){
        A[i] = A[i] = A[i-1]+A[i-2]+A[i-3];
    }
    cout << A[to-1] << endl;
    return 0;
}