#include <bits/stdc++.h>
using namespace std;
#define rep(i,l,r) for(int i=(l);i<(r);++i)
typedef long long ll;

int main(){
	int a,b,c,d,e; cin>>a>>b>>c>>d>>e;
	if(b-c==0) {cout<<0<<endl; return 0;}
	int r=(b-c)*a;
	int x=d, ans=d;
	rep(i,2,r+1){
		if(i%10!=0) ans+=x;
		if(i%10==0&&e<=x) ans+=(x-e);
		if(i%10==0&&e>x) ans+=x;
	}
	cout<<ans<<endl;
}