#include <cstdio>
#include <algorithm>
#include <iostream>
using namespace std;

long long i, j, n, x, y, fx, fy, tmp;
long long a[2] = {1,0};
int b[2] = {0,1};

long long find(long long v){
	if (v == x)
		return fx;
	if (v == x + 1)
		return fy;
	if (v > x + 1){
		for (i = x + 2; i <= v; i++){
			tmp = fy;
			fy += fx;
			fx = tmp;
		}
		return fy;
	}
	for (i = x - 1; i >= v; i--){
		tmp = fx;
		fx = fy - fx;
		fy = tmp;
	}
	return fx;
}

int main(){
	cin >> x >> fx >> y >> fy >> n;
	if (x > y){
		swap(x,y);
		swap(fx,fy);
	}

	a[0] = b[1] = 1;

	for (i = x + 2; i <= y; i++)
		for (j = 0; j < 2; j++){
			tmp = b[j];
			b[j] += a[j];
			a[j] = tmp;
		}

	fy = (fy - b[0] * fx) / b[1];
	cout << find(n) << endl;
	return 0;
}