Finally Fox Ciel arrived in front of her castle!

She have to type a password to enter her castle. An input device attached to her castle is a bit unusual.

The input device is a 1 × *n* rectangle divided into *n* square panels. They are numbered 1 to *n* from left to right. Each panel has a state either ON or OFF. Initially all panels are in the OFF state. She can enter her castle if and only if *x*<sub class="lower-index">1</sub>-th, *x*<sub class="lower-index">2</sub>-th, ..., *x*<sub class="lower-index">*k*</sub>-th panels are in the ON state and other panels are in the OFF state.

She is given an array *a*<sub class="lower-index">1</sub>, ..., *a*<sub class="lower-index">*l*</sub>. In each move, she can perform the following operation: choose an index *i* (1 ≤ *i* ≤ *l*), choose consecutive *a*<sub class="lower-index">*i*</sub> panels, and flip the states of those panels (i.e. ON → OFF, OFF → ON).

Unfortunately she forgets how to type the password with only above operations. Determine the minimal number of operations required to enter her castle.
The first line contains three integers *n*, *k* and *l* (1 ≤ *n* ≤ 10000, 1 ≤ *k* ≤ 10, 1 ≤ *l* ≤ 100), separated by single spaces.

The second line contains *k* integers *x*<sub class="lower-index">1</sub>, ..., *x*<sub class="lower-index">*k*</sub> (1 ≤ *x*<sub class="lower-index">1</sub> &lt; *x*<sub class="lower-index">2</sub> &lt; ... &lt; *x*<sub class="lower-index">*k*</sub> ≤ *n*), separated by single spaces.

The third line contains *l* integers *a*<sub class="lower-index">1</sub>, ..., *a*<sub class="lower-index">*l*</sub> (1 ≤ *a*<sub class="lower-index">*i*</sub> ≤ *n*), separated by single spaces. It is possible that some elements of the array *a*<sub class="lower-index">*i*</sub> are equal value.
One possible way to type the password in the first example is following: In the first move, choose 1st, 2nd, 3rd panels and flip those panels. In the second move, choose 5th, 6th, 7th, 8th, 9th panels and flip those panels.

from collections import Counter 
ans=float('inf')
def recur(b,pos,cost):
    global ans
    # print(b,pos,cost)
    t=list(b)
    if pos==n-1:
        ans=min(ans,cost+(1 if t[pos]==1 else 0))
    elif t[pos]==0:
        recur(b,pos+1,cost)
    else:
        t[pos]=0
        for d in al:
            if pos+d<n:
                t[pos+d]^=1
                recur(tuple(t),pos+1,cost+1)
                t[pos+d]^=1


n,k,l=map(int,input().split())
arr=list(map(int,input().split()))
al=list(map(int,input().split() ))
b=[0]*(n+1)
for i in range(k):
    b[arr[i]]=1  

# print(b)
for  j in range(n):
    if b[j]!=b[j+1]:
        b[j]=1
    else:
        b[j]=0

# print(b)
recur(tuple(b),0,0)
if ans==float('inf'):
    print(-1)
else:
    print(ans)






    
        
