Cow Picnic

The cows are having a picnic! Each of Farmer John's K cows (1 ≤ K ≤ 100) is grazing in one of N pastures (1 ≤ N ≤ 1,000), conveniently numbered 1 through N. The pastures are connected by M (1 ≤ M ≤ 10,000) one-way paths, and no path connects a pasture to itself.

The cows want to gather in the same pasture for their picnic, but because the paths are one-way, some cows may only be able to reach certain pastures. Determine how many pastures are reachable by every cow, and hence are possible picnic locations.

• Line 1: Three space-separated integers K, N, and M.
• Lines 2 to K+1: Line i+1 contains a single integer (from 1 to N), the number of the pasture in which cow i is grazing.
• Lines K+2 to M+K+1: Each line contains two space-separated integers A and B (both from 1 to N, with A ≠ B), representing a one-way path from pasture A to pasture B.

• Line 1: A single integer, the number of pastures that are reachable by all cows using the one-way paths.

In the example, the cows can meet in pasture 3 or pasture 4, so there are 2 possible picnic locations.