#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 */   
    long int sum=1;
    int i,a,b,t=0;
    cin>>a>>b>>t;
    for(i=0;i<t;i++)
        {
        sum=((0.5*a*sum)+(0.5*b*sum));
    }
    sum=sum % 1000000007;
    cout<<sum;
    return 0;
}