#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define LLINF 9223372036854775807
#define MOD ll(1e9+7)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cerr<<#x<<": "<<x<<endl

typedef vector<vector<ll>> matrix;

matrix mul(matrix &a, matrix &b){
    matrix ret(a.size(), vector<ll>(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++){
                ret[i][j] = (ret[i][j] + a[i][k]*b[k][j])%MOD;
            }
        }
    }
    return ret;
}

matrix matpow(matrix a, ll n){
    matrix ret(a.size(), vector<ll>(a.size()));
    for(int i = 0; i < a.size(); i++){
        ret[i][i] = 1;
    }
    while(n>0){
        if(n&1){
            ret = mul(ret, a);
        }
        a = mul(a, a);
        n = n >> 1;
    }
    return ret;
}


int main(){
    ll a, b, n;
    cin >> a >> b >> n;

    matrix m(2,vector<ll>(2));
    m[0][0] = a; m[0][1] = b;
    m[1][0] = 1; m[1][1] = 0;
    matrix mpow = matpow(m, n);
    ll ans = mpow[1][0];
    cout << ans%MOD << endl;
    return 0;

}