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 di meters. The feeders live in hill 1.
One day, the cats went out to play. Cat i went on a trip to hill hi, finished its trip at time ti, and then waited at hill hi 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 (d2=1) and one cat that finished its trip at time 3 at hill 2 (h1=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 d2,d3,...,dn (1≤di<104).
Each of the next m lines contains two integers hi and ti (1≤hi≤n,0≤ti≤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 C++. 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
3