#include <iostream>
#include <conio.h>
using namespace std;

void find(int j, int i, int &k1,int &k2)
{
     if (j==i+1) return;
     else
     {
         int buf = k1;
         k1 = k1 + k2;
         k2 = buf;
         find(j-1,i,k1,k2);
    }
}

int main()
{
     long long Fi, Fj, f1,f2, f3;
     int i,j,n;
     cin>>i>>Fi>>j>>Fj>>n;
    if (j==n)  {cout<<Fj<<endl; return 0;}
    if (i==n)  {cout<<Fi<<endl; return 0;}
     if (i<j)
     {
               int buf = i;
               i = j;
               j = buf;
               buf = Fi;
               Fi = Fj;
               Fj = buf;
    }
     int k1 = 1, k2 = 1;
     f1 = Fj;
     if (i!=j+1)
     {
        find(i-1,j,k1,k2);
        f2 = (Fi - k2*Fj)/k1;
     }
    else
        f2 = Fi;

     int lim;
     if (j<0) lim = n - j -1;
     else
     if (j == 0 ) lim = n;
     else lim = n - j +1;
     for (int count = j +1; count < lim; count++)
    {
         f3 = f1 + f2;
         f1 = f2;
         f2 = f3;
    }
     cout<<f3<<endl;
     return 0;
}