#include<iostream> using namespace std; int main() { int a[10001]; int n,m,x; cin>>a[0]>>n>>m>>x; a[1]=a[0]; for(int i=2;i<n;i++) { a[i]+=a[i-2]; a[i]+=a[i-1]; //cout<<a[i]<<" "; if(i==x-1) { //cout<<endl; cout<<a[i]; return 0; } } cout<<"No answer."<<endl; return 0; }