#include<bits/stdc++.h>

using namespace std;
using ll=long long;

template<typename T, typename U>
T floor(T x, U y){return (x>0 ? x/y: (x-y+1)/y);}

template<typename T, typename U>
T ceil(T x, U y){return (x>0 ? (x+y-1)/y: x/y);}

template<typename T, typename U>
pair<T,T> divmod(T x, U y){
    T q=floor(x,y);
    return {q,x-q*y};
}

int main(){
    ll T,A,B,X,Y;
    cin >> T >> X >> A >> Y >> B;

    ll Ans=1001001001001001001;
    for (int r=0; r<=30000000; r++){
        ll q,p;
        tie (q,p)=divmod(T+r*B, A);
        Ans=min(Ans, p+q*X+r*Y);
    }

    cout << Ans << endl;
}