#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;

typedef long long ll;

ll a, b, n, MOD = 1e9 + 7;
map<ll, ll> mp;

ll mod_pow(ll x, ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

ll solve(ll n) {
    if (mp.find(n) != mp.end()) return mp[n];
    if (n == 0) {
        mp[0] = 2;
        return mp[0];
    }
    if (n == 1) {
        mp[1] = (2 * a) % MOD;
        return mp[1];
    }
    if (n % 2) {
        mp[n] = (solve(n / 2 + 1) * solve(n / 2) - ((mod_pow(a * a - b, n / 2, MOD) * 2 * a) % MOD) + MOD) % MOD;
    } else {
        mp[n] = (solve(n / 2) * solve(n / 2) - ((mod_pow(a * a - b, n / 2, MOD) * 2) % MOD) + MOD) % MOD;
    }
    return mp[n];
}

int main() {
    cin >> a >> b >> n;
    if (a == 0) {
        if (b == 0) {
            cout << "0\n";
            return 0;
        } else {
            if (n % 2) {
                cout << "0\n";
                return 0;
            } else {
                cout << (mod_pow(b, n / 2, MOD) * 2) % MOD << "\n";
                return 0;
            }
        }
    }
    if (b == 0) {
        cout << (mod_pow(a, n, MOD) * 2) % MOD << "\n";
        return 0;
    }
    cout << solve(n) << "\n";
}