#include using namespace std; typedef long long ll; #define INF (long long)(1e9+7) #define REP(i,n) for(ll i = 0; i < n; i++) #define REP1(i,n) for(ll i = 1; i <= n; i++) int main(void) { ll a,b,x0,n; cin >> a >> b >> x0 >> n; ll p = n / 2; if(x0 % 2 != 0) { cout<