import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        long bb = sc.nextLong() % MOD;
        long cc = sc.nextLong() % MOD;
        long dd = sc.nextLong();
        long[][][] matrix = new long[60][2][2];
        matrix[0] = new long[][]{{cc, cc}, {0, 1}};
        for (int i = 1; i < 60; i++) {
            for (int a = 0; a < 2; a++) {
                for (int b = 0; b < 2; b++) {
                    for (int c = 0; c < 2; c++) {
                        matrix[i][a][c] += matrix[i - 1][a][b] * matrix[i - 1][b][c] % MOD;
                        matrix[i][a][c] %= MOD;
                    }
                }
            }
        }
        long[] ans = new long[]{0, bb};
        for (int i = 59; i >= 0; i--) {
            if (dd < (1L << i)) {
                continue;
            }
            dd -= (1L << i);
            long[] next = new long[2];
            for (int a = 0; a < 2; a++) {
                for (int b = 0; b < 2; b++) {
                    next[a] += matrix[i][a][b] * ans[b] % MOD;
                    next[a] %= MOD;
                }
            }
            ans = next;
        }
        System.out.println(ans[0]);
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}