#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define inf (int)(1e9+7)
#define abs(x) (x >= 0 ? x : -(x))
#define ceil(a, b) a / b + !!(a % b)
template<typename T1, typename T2> inline void chmin(T1 &a, T2 b) { if (a > b) a = b; }
template<typename T1, typename T2> inline void chmax(T1 &a, T2 b) { if (a < b) a = b; }
template<typename T> T pow(T a, int b) { return b ? pow(a * a, b / 2) * (b % 2 ? a : 1) : 1; }
template<typename T> T gcd(T a, T b) { if (b == 0) return a; return gcd(b, a % b); }


const ll mod = 1e9 + 7;

int modpow(int a, int b) {
    if (b == 0) return 1;
    return (modpow((ll)a * a % mod, b / 2) % mod * (b % 2 ? a : 1) % mod) % mod;
}


int main() {
    int a, b, n;
    cin >> a >> b >> n;
    
    if (a == 0 && b == 0) {
        cout << 0 << endl;
        return 0;
    } else if (a == 0) {
        if (n % 2 == 0) cout << 0 << endl;
        else {
            cout << modpow(b, n / 2) << endl;
        }
        return 0;
    } else if (b == 0) {
        cout << modpow(a, n - 1) << endl;
        return 0;
    }
    double al, be;
    al = (a + sqrt(a * a + 4 * b)) / 2;
    be = (a - sqrt(a * a + 4 * b)) / 2;
    // cout << al << " " << be << endl;
    ll x = 0, y = 1;
    rep3(i, 2, n + 1) {
        ll z = (ll)((al * y + pow(be, i - 1)) + mod) % mod;
        // cout << pow(be, i - 1) << " " << z << endl;
        x = y;
        y = z;
    }
    cout << y << endl;
}