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B. Cats Transport
time limit per test
2 seconds
memory limit per test
256 megabytes
standard input
standard output

Zxr960115 is owner of a large farm. He feeds m cute cats and employs p feeders. There's a straight road across the farm and n hills along the road, numbered from 1 to n from left to right. The distance between hill i and (i - 1) is d i meters. The feeders live in hill 1.

One day, the cats went out to play. Cat i went on a trip to hill h i, finished its trip at time t i, and then waited at hill h i for a feeder. The feeders must take all the cats. Each feeder goes straightly from hill 1 to n without waiting at a hill and takes all the waiting cats at each hill away. Feeders walk at a speed of 1 meter per unit time and are strong enough to take as many cats as they want.

For example, suppose we have two hills (d 2 = 1) and one cat that finished its trip at time 3 at hill 2 (h 1 = 2). Then if the feeder leaves hill 1 at time 2 or at time 3, he can take this cat, but if he leaves hill 1 at time 1 he can't take it. If the feeder leaves hill 1 at time 2, the cat waits him for 0 time units, if the feeder leaves hill 1 at time 3, the cat waits him for 1 time units.

Your task is to schedule the time leaving from hill 1 for each feeder so that the sum of the waiting time of all cats is minimized.


The first line of the input contains three integers n, m, p (2 ≤ n ≤ 105, 1 ≤ m ≤ 105, 1 ≤ p ≤ 100).

The second line contains n - 1 positive integers d 2, d 3, ..., d n (1 ≤ d i < 104).

Each of the next m lines contains two integers h i and t i (1 ≤ h i ≤ n, 0 ≤ t i ≤ 109).


Output an integer, the minimum sum of waiting time of all cats.

Please, do not write the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.

4 6 2
1 3 5
1 0
2 1
4 9
1 10
2 10
3 12