#include <bits/stdc++.h> using namespace std; int main(){ long long b,a,n,a1,a2,b1,b2,Min; cin>> n >> a1 >> a2 >>b1 >> b2; if( n % a1 == 0) a = ( n / a1 ) * a2; else if( n % a1 != 0) a = (( n / a1 ) + 1) * a2; Min = a; if( n % b1 == 0) b = ( n / b1 ) * a2; else if( n % b1 != 0) b = (( n / b1 ) + 1) * b2; if( Min > b ) Min = b; cout<< Min ;

}