def min_fuel_cost(dist, prices, fuel_tank):
    n = len(prices)
    fuel = 0 
    cost = 0

    for i in range(n - 1):
        need = 0
        found = False

        for j in range(i + 1, n):
            need += dist[j - 1]
            if prices[j] < prices[i]:
                found = True
                break

        if found:
            target = need
            target = fuel_tank

        if fuel < target:
            buy = target - fuel
            cost += buy * prices[i]
            fuel = target

        fuel -= dist[i]

    return cost

dist = [2, 3, 1]
prices = [5, 2, 4, 1]
fuel_tank = 10

print(min_fuel_cost(dist, prices, fuel_tank))