// #define DEBUGGING
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()

template <typename T> using V = vector<T>;
template <typename T> using VV = V<V<T>>;
using ll = int64_t;
using ull = uint64_t;
using PLL = pair<ll, ll>;

template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return max(low, min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { t = clamp(t, low, high); }

namespace init__ {

struct InitIO {
    InitIO() {
        cin.tie(nullptr);
        ios_base::sync_with_stdio(false);
        cout << fixed << setprecision(30);
    }
} init_io;

}

#ifdef DEBUGGING
// #include "../debug/debug.cpp"
#include "../../debug/debug.cpp"
#else
#define DEBUG(...) 0
#define DEBUG_SEPARATOR_LINE 0
#endif

template <typename T>
T make_v(T init) { return init; }

template <typename T, typename... Tail>
auto make_v(T init, size_t s, Tail... tail) {
#define rec make_v(init, tail...)
    return V<decltype(rec)>(s, rec);
#undef rec
}

using Mat = VV<ll>;

const ll mod = 1e9 + 7;

Mat mul(const Mat &ma, const Mat &mb) {
    Mat ret = make_v<ll>(0, ma.size(), mb[0].size());
    for(ll i = 0; i < ma.size(); i++) {
        for(ll j = 0; j < mb[0].size(); j++) {
            for(ll k = 0; k < mb.size(); k++) {
                (ret[i][j] += ma[i][k] * mb[k][j]) %= mod;
            }
        }
    }
    return ret;
}

Mat pow__(Mat n, ll k) {
    Mat ret = make_v<ll>(0, n.size(), n.size());
    for(ll i = 0; i < ret.size(); i++) ret[i][i] = 1;
    if(k == 0) return ret;
    if(k & 1) ret = mul(ret, n);
    auto rec = pow__(mul(n, n), k / 2);
    return mul(ret, rec);
}

ll solve() {
    ll a, b, n;
    cin >> a >> b >> n;
    if(n == 0) return 0;
    if(n == 1) return 1;
    Mat mat = {
        { a, b, },
        { 1, 0, },
    };
    mat = pow__(mat, n - 1);
    return mat[0][0];
}

int main() { 
    cout << solve() << endl;
    return 0;
}