#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int a, b;
    uint64_t t;
    cin >> a >> b;
    cin >> t;
    uint64_t x= (a + b) / 2; /* ((a + b) / 2)^t is guaranteed to be integer, then since 2 is prime (a + b) % 2 == 0 */
    /* Calculate x^t via exponentiation by squaring - O(log(t)) */
    uint64_t y= 1;
    while (t > 1) {
        if (t % 2 != 0) {
            t--;
            y*= x;
            y%= 1000000007ULL;
        }
        x*= x;
        t/= 2;
        x%= 1000000007ULL;
    }
    x*= y;
    x%= 1000000007ULL;
    cout << x << endl;
    return 0;
}