#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int a,b,c,d,e,s=0; cin>>e>>a>>b>>c>>d; if(b-a==c-b){ s=d; for(int i=a;i<=e-1;i++) { s+=b-a; } cout<<s; } else{ if(b/a==c/b){ s=d; for(int i=a;i<=e-1;i++) { s+=b/a; } cout<<s; } } return 0; }