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

typedef struct node {
    unsigned long long n;
    struct node* next;
} node;

typedef struct node* Node;

Node newNode (int n);
Node append (Node head, Node n);
void printList (Node head);

int main() {

    int a, b, t;
    scanf("%d %d %d", &a, &b, &t);
    
    Node head = malloc(sizeof(node));
    head->n = 1;
    head->next = NULL;
    unsigned long long values = 1;
    
    for (int i = 0; i < t; i++){
        values *= 2;
        //printList(head);
        Node expanding = head;
        head = NULL;
        
        while (expanding != NULL){
            head = append(head, newNode(expanding->n * a));
            head = append(head, newNode(expanding->n * b));
            expanding = expanding->next;
        }
    }
    
    //printList(head);
    unsigned long long expected = 0;
    while (head != NULL){
        expected += head->n;
        head = head ->next;
    }
    printf("%llu\n", expected / values);
    
    return 0;
}

Node newNode (int n){
    Node new = malloc(sizeof(node));
    new->next = NULL;
    new->n = n;
    
    return new;
}

Node append (Node head, Node n){
    
    if (head){
        while (head->next != NULL){
            head = head->next;
        }
        head->next = n;
    } else {
        head = n;
    }
    
    return head;
}

void printList (Node head){
    while (head != NULL){
        printf("%llu->", head->n);
        head = head->next;
    }
    printf("X\n");
}