#include <iostream>
#include <fstream>
#include <deque>
#include <numeric>

using namespace std;

ifstream input_stream;
ofstream output_stream;


uint64_t dequeSum(deque<uint64_t> &d) {
	return accumulate(d.begin(), d.end(), 0);
}

int main() {
	input_stream.open("input.txt");
	output_stream.open("output.txt");

	uint16_t P, T, N;
	input_stream >> P;
	input_stream >> T;
	input_stream >> N;

	deque<uint64_t> bacteria;
	bacteria.push_front(P);

	uint16_t i;
	uint64_t mature = 0;

	// Populate list until death of first generation
	for (i=1; i < T && i <= N; i++) {
		// Reproduction
		bacteria.push_front(mature);

		// Maturity
		mature += bacteria[1];
	}

	// Run loop considering death until experiment is complete
	for(i; i <= N; i++) {
		// Reproduction
		bacteria.push_front(mature);

		// Death
		mature -= bacteria.back();
		bacteria.pop_back();

		// Maturity
		mature += bacteria[1];
	}

	output_stream << dequeSum(bacteria) << endl;

	input_stream.close();
	output_stream.close();
	return 0;
}