#include <bits/stdc++.h>
using namespace std;
using ll = long long;

ll solve() {
    ll P, Q, R, K;
    cin >> P >> Q >> R >> K;

    using Int = ll;
    auto matmul = [&](vector<vector<Int>>& t, vector<vector<Int>>& m) -> vector<vector<Int> > {
        vector<vector<Int>> ret(t.size(), vector<Int>(m[0].size()));
        for ( int r = 0; r < t.size(); r++ ) {
            for ( int c = 0; c < m[0].size(); c++ ) {
                for ( int k = 0; k < m.size(); k++ ) {
                    ret[r][c] += t[r][k] * m[k][c];
                }
                ret[r][c] %= 10;
            }
        }
        return ret;
    };

    auto matpow = [&](vector<vector<Int>>& tt, ll n) -> vector<vector<Int>> {
        ll d = tt.size();
        vector<vector<Int>> ret(d, vector<Int>(d));
        vector<vector<Int>> t(d, vector<Int>(d));
        for ( int i = 0; i < d; i++ ) {
            ret[i][i] = 1;
        }
        for ( int i = 0; i < d; i++ ) {
            for ( int j = 0; j < d; j++ ) {
                t[i][j] = tt[i][j];
            }
        }
        while ( n > 0 ) {
            if ( n & 1 ) ret = matmul(ret,t);
            t = matmul(t,t);
            n >>= 1;
        }
        return ret;
    };

    vector<vector<ll>> t(3, vector<ll>(3));
    t[0][1] = 1;
    t[1][2] = 1;
    t[2][0] = 1;
    t[2][1] = 1;
    t[2][2] = 1;
    auto tt = matpow(t, K-1);
    vector<vector<ll>> v = {{P%10}, {Q%10}, {R%10}};
    auto ans = matmul(tt, v);
    return ans[0][0];
}

int main() {
    auto ans = solve();
    cout << ans << "\n";
    return 0;
}