Farmer** John** needs to travel to town to pick up K (1 <= K <= 100)pounds of
feed. Driving D miles with K pounds of feed in his truck costs **D*K** cents.

The
county feed lot has N (1 <= N<= 100) stores (conveniently
numbered 1..N) that sell feed. Each store is located on a segment of the
X axis whose length is E (1 <= E <= 350). Store i is at location X_i (0 < X_i < E) on the number line and can sell **John** as much as F_i (1 <= F_i <= 100) pounds of feed at a cost of C_i (1 <= C_i <= 1,000,000) cents per pound.

Amazingly, a given point on the X axis might have more than one store.

Farmer** John ** starts at
location 0 on this number line and can drive only in the positive
direction, ultimately arriving at location E, with at least **K** pounds of feed. He can stop at any of the feed stores along the way and buy any amount of feed up to the the store's limit. What is the minimum amount Farmer **John** has to pay to buy and transport the K pounds of feed? Farmer** John**

knows there is a solution. Consider a sample where Farmer** John **needs two pounds of feed from three stores (locations: 1, 3, and 4) on a number line whose range is 0..5:

0 1 2 3 4 5

---------------------------------

1 1 1 Available pounds of feed

1 2 2 Cents per pound

It is best for **John** to buy one pound of feed from both the second and third stores. He must
pay two cents to buy each pound of feed for a total cost of 4. When** John** travels from 3 to 4 he is moving 1 unit of length and he has 1 pound of feed so he must pay1*1 = 1 cents.

**John**travels from 4 to 5 heis moving one unit and he has 2 pounds of feed so he must pay 1*2 = 2 cents. The total cost is 4+1+2 = 7 cents.