#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
 
int main(){
    int N;     // 必要な卵の個数
    int S, A;  // S個入りパックが A円
    int M, B;  // M個入りパックが B円
    int L, C;  // L個入りパックが C円
 
    if (scanf("%d", &N) != 1) return 0;
    scanf("%d %d", &S, &A);
    scanf("%d %d", &M, &B);
    scanf("%d %d", &L, &C);
 
    // Sパックを i 個買うときの上限 i_max, Mパックを j 個買うときの上限 j_max
    int i_max = (N + S - 1) / S;
    int j_max = (N + M - 1) / M;
 
    int best = INT_MAX;
 
    // Sパックと Mパックの組み合わせを全探索
    // 残りを Lパックで賄う k を定数時間で算出
    for (int i = 0; i <= i_max; i++) {
        int eggs_i = i * S;
        for (int j = 0; j <= j_max; j++) {
            int eggs_ij = eggs_i + j * M;
 
            // 必要数に満たない分を Lパックで補う個数 k を計算
            int k = 0;
            if (eggs_ij < N) {
                k = (N - eggs_ij + L - 1) / L;
            }
 
            int cost = i * A + j * B + k * C;
            if (cost < best) {
                best = cost;
            }
        }
    }
 
    // 最小コストのみ出力
    printf("%d\n", best);
    return 0;
}

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20
6 120
8 150
10 180