using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using static System.Console;
using static System.Convert;
using static System.Math;
//using static System.Globalization.CultureInfo;
using System.Text;
class Program
{
    public static bool chmin<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == 1) { num = val; return true; } return false; }
    public static bool chmax<T>(ref T num, T val) where T : IComparable<T>
    { if (num.CompareTo(val) == -1) { num = val; return true; } return false; }
    public static void swap<T>(ref T v1, ref T v2)
    { var t = v2; v2 = v1; v1 = t; }
    public static void Fail() { WriteLine("No"); Console.Out.Close(); Environment.Exit(0); }
    static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        var p = new Program();
        for (var i = 1; i > 0; --i)
            p.Solve();
        Console.Out.Flush();
    }
    void Solve()
    {
        int a, b, n;
        Input.Make(out a, out b, out n);
        var mt = new Matrix(2, 2);
        mt[0][0] = a;
        mt[0][1] = b;
        mt[1][0] = 1;
        WriteLine(mt.Pow(n)[1][0]);
    }
}

public class Matrix
{
    private long[][] item { get; }
    public int Height { get; }
    public int Width { get; }
    public static long e { get; set; }
    public static Func<long, long, long> add { get; set; }
    public static Func<long, long, long> mul { get; set; }
    public long[] this[int i]
    { get { return item[i]; } set { item[i] = value; } }
    public long this[int i1, int i2]
    {
        get { return item[i1][i2]; }
        set { item[i1][i2] = value; }
    }
    public Matrix(int height, int width)
    {
        Height = height;
        Width = width;
        item = Enumerable.Repeat(0, height).Select(_ => new long[width]).ToArray();
    }
    static Matrix() { var mod = (int)1e9 + 7; e = 1; add = (a, b) => (a + b) % mod; mul = (a, b) => a * b % mod; }
    public static Matrix E(int size)
    {
        var tm = new Matrix(size, size);
        for (var i = 0; i < size; i++)
            tm[i, i] = e;
        return tm;
    }
    public static Matrix Trans(Matrix m)
    {
        var n = m.Width; var p = m.Height;
        var tm = new Matrix(n, p);
        for (var i = 0; i < n; i++)
        {
            for (var j = 0; j < p; j++)
                tm[i, j] = m[j, i];
        }
        return tm;
    }
    public static long Dot(long[] ar1, long[] ar2)
    {
        var tm = 0L;
        for (var i = 0; i < ar1.Length; i++)
            tm = add(tm, mul(ar1[i], ar2[i]));
        return tm;
    }
    public static Matrix Add(Matrix m1, Matrix m2)
    {
        var tm = new Matrix(m1.Height, m1.Width);
        for (var i = 0; i < m1.Height; i++)
            for (var j = 0; j < m1.Width; j++)
                tm[i, j] = add(m1[i, j], m2[i, j]);
        return tm;
    }
    public static long[] Mul(Matrix m, long[] ar)
        => Enumerable.Range(0, m.Height).Select(v => Dot(m[v], ar)).ToArray();
    public static Matrix Mul(Matrix m1, Matrix m2)
    {
        var tr = Trans(m2);
        var tm = new Matrix(m1.Height, m2.Width);
        for (var i = 0; i < m1.Height; i++)
            tm[i] = Mul(tr, m1[i]);
        return tm;
    }
    public static Matrix operator +(Matrix l, Matrix r)
        => Add(l, r);
    public static Matrix operator *(Matrix l, Matrix r)
        => Mul(l, r);
    public static long[] operator *(Matrix l, long[] r)
        => Mul(l, r);
    public Matrix Pow(long n)
    {
        if (n == 0) return E(Height);
        var tm = Pow(n / 2);
        if (n % 2 == 0) return Mul(tm, tm);
        else return Mul(Mul(tm, tm), this);
    }
}

public class Input
{
    public static string read => ReadLine().Trim();
    public static int[] ar => read.Split(' ').Select(int.Parse).ToArray();
    public static int num => ToInt32(read);
    public static long[] arL => read.Split(' ').Select(long.Parse).ToArray();
    public static long numL => ToInt64(read);
    public static T[] create<T>(int n, Func<int, T> f)
        => Enumerable.Repeat(0, n).Select(f).ToArray();
    public static char[][] grid(int h)
        => create(h, _ => read.ToCharArray());
    public static int[] ar1D(int n)
        => create(n, _ => num);
    public static long[] arL1D(int n)
        => create(n, _ => numL);
    public static string[] strs(int n)
        => create(n, _ => read);
    public static int[][] ar2D(int n)
        => create(n, _ => ar);
    public static long[][] arL2D(int n)
        => create(n, _ => arL);
    public static List<T>[] edge<T>(int n)
        => create(n, _ => new List<T>());
    public static T GetValue<T>(string g)
    {
        var t = typeof(T);
        if (t == typeof(int))
            return (T)(object)int.Parse(g);
        if (t == typeof(long))
            return (T)(object)long.Parse(g);
        if (t == typeof(string))
            return (T)(object)g;
        if (t == typeof(char))
            return (T)(object)char.Parse(g);
        if (t == typeof(double))
            return (T)(object)double.Parse(g);
        if (t == typeof(bool))
            return (T)(object)bool.Parse(g);
        return default(T);
    }
    public static void Make<T1, T2>(out T1 v1, out T2 v2)
    {
        v1 = Next<T1>();
        v2 = Next<T2>();
    }
    public static void Make<T1, T2, T3>(out T1 v1, out T2 v2, out T3 v3)
    {
        Make(out v1, out v2);
        v3 = Next<T3>();
    }
    public static void Make<T1, T2, T3, T4>(out T1 v1, out T2 v2, out T3 v3, out T4 v4)
    {
        Make(out v1, out v2, out v3);
        v4 = Next<T4>();
    }
    public static void Make<T1, T2, T3, T4, T5>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5)
    {
        Make(out v1, out v2, out v3, out v4);
        v5 = Next<T5>();
    }
    public static void Make<T1, T2, T3, T4, T5, T6>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5, out T6 v6)
    {
        Make(out v1, out v2, out v3, out v4, out v5);
        v6 = Next<T6>();
    }
    private static Queue<string> sc;
    public static T Next<T>() { sc = sc ?? new Queue<string>(); if (sc.Count == 0) foreach (var item in read.Split(' ')) sc.Enqueue(item); return GetValue<T>(sc.Dequeue()); }
    public static void Next<T>(ref T val) => val = Next<T>();
    public const long Inf = (long)1e18;
    public const double eps = 1e-6;
    public const string Alfa = "abcdefghijklmnopqrstuvwxyz";
    public const int MOD = 1000000007;
}

public class Pair<T1, T2> : IComparable<Pair<T1, T2>>
{
    public T1 v1 { get; set; }
    public T2 v2 { get; set; }
    public Pair() { v1 = Input.Next<T1>(); v2 = Input.Next<T2>(); }
    public Pair(T1 v1, T2 v2)
    { this.v1 = v1; this.v2 = v2; }

    public int CompareTo(Pair<T1, T2> p)
    {
        var c = Comparer<T1>.Default.Compare(v1, p.v1);
        if (c == 0)
            c = Comparer<T2>.Default.Compare(v2, p.v2);
        return c;
    }
    public override string ToString()
        => $"{v1.ToString()} {v2.ToString()}";
    public override bool Equals(object obj)
        => this == (Pair<T1, T2>)obj;
    public override int GetHashCode()
        => v1.GetHashCode() ^ v2.GetHashCode();
    public static bool operator ==(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == 0;
    public static bool operator !=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != 0;
    public static bool operator >(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == 1;
    public static bool operator >=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != -1;
    public static bool operator <(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) == -1;
    public static bool operator <=(Pair<T1, T2> p1, Pair<T1, T2> p2)
        => p1.CompareTo(p2) != 1;
}

public class Pair<T1, T2, T3> : Pair<T1, T2>, IComparable<Pair<T1, T2, T3>>
{
    public T3 v3 { get; set; }
    public Pair() : base() { v3 = Input.Next<T3>(); }
    public Pair(T1 v1, T2 v2, T3 v3) : base(v1, v2)
    { this.v3 = v3; }

    public int CompareTo(Pair<T1, T2, T3> p)
    {
        var c = base.CompareTo(p);
        if (c == 0)
            c = Comparer<T3>.Default.Compare(v3, p.v3);
        return c;
    }
    public override string ToString()
        => $"{base.ToString()} {v3.ToString()}";
}