#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    int i,a,b,t;
    scanf("%d",&a);
    scanf("%d",&b);
    scanf("%d",&t);
    long long int count=1,fcount=1;
    for(i=0;i<t;i++)
        {
        count=0.5*a*count+0.5*b*count;
         //printf("%lld",count);
        if(count>=(10^9)+7)
        {count=count%((10^9)+7);}
      
        
    }
    printf("%lld",count);
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}