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


#define int long long

typedef vector<int> vec;
typedef vector<vec> mat;

#define MOD 1000000007

mat mul(mat &a, mat &b){
    mat c(a.size(), vec(b[0].size()));
    for(int i = 0;i < a.size();i++){
        for(int k = 0;k < b.size();k++){
            for(int j = 0;j < b[0].size();j++){
                c[i][j] = (c[i][j] + (a[i][k] * b[k][j]) % MOD) % MOD;
            }
        }
    }
    return c;
}

mat pow(mat a, int n){
    mat b(a.size(), vec(a.size()));
    for(int i = 0;i < a.size();i++){
        b[i][i] = 1;
    }

    while(n > 0){
        if(n & 1) b = mul(b, a);
        a = mul(a, a);
        n >>= 1;
    }

    return b;
}

signed main(){
    mat a(2, vec(2));
    int x, b, n;
    cin >> x >> b >> n;
    a[0][0] = x, a[0][1] = b;
    a[1][0] = 1, a[1][1] = 0;
    a = pow(a, n);
    cout << a[1][0] << endl;
    return 0;
}