#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;
    long long int t;
    int count=1;
    cin>>a>>b;
    cin>>t;
    while(t>0){
        count=((0.5*a*count)+(0.5*b*count));
        t--;
    }
    count=count%((int)(pow(10,9)+7));
    cout<<count;
    return 0;
}