#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> P;
int a, b;
ll n;
const int md = (int)1e9 + 7;
#define ADD(x, y) (x + y) % md
#define MUL(x, y) (x * y) % md
P f(P l, P r) {
    return P(ADD(MUL(l.first, r.first), MUL(MUL(l.second, r.second), b)),
             ADD(MUL(l.first, r.second), MUL(l.second, r.first)));
}
P g(P l, ll n) {
    P t(1, 0);
    while (n) {
        if (n & 1) t = f(t, l);
        l = f(l, l);
        n >>= 1;
    }
    return t;
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> a >> b >> n;
    P s = g(P(a, 1), n);
    P t = g(P(a, -1), n);
    ll m = ADD(s.first, t.first);
    cout << m << "\n";
}