import itertools

def main():
    import sys
    input = sys.stdin.read().split()
    ptr = 0
    N = int(input[ptr])
    ptr += 1
    A = list(map(int, input[ptr:ptr+N]))
    ptr += N
    M = int(input[ptr])
    ptr += 1
    B = list(map(int, input[ptr:ptr+M]))
    ptr += M
    
    sumA = sum(A)
    if not B:
        print(-1)
        return
    maxB = max(B)
    if any(a > maxB for a in A):
        print(-1)
        return
    sumB = sum(B)
    if sumA > sumB:
        print(-1)
        return
    
    maxA = max(A)
    
    for k in range(1, M + 1):
        for combo in itertools.combinations(B, k):
            sumC = sum(combo)
            if sumC < sumA:
                continue
            maxC = max(combo)
            if maxC < maxA:
                continue
            toys_sorted = sorted(A, reverse=True)
            boxes_sorted = sorted(combo, reverse=True)
            
            memo = {}
            
            def backtrack(index, remaining):
                if index == len(toys_sorted):
                    return True
                current_toy = toys_sorted[index]
                key = (index, tuple(remaining))
                if key in memo:
                    return memo[key]
                for i in range(len(remaining)):
                    if i > 0 and remaining[i] == remaining[i-1]:
                        continue
                    if remaining[i] >= current_toy:
                        new_remaining = list(remaining)
                        new_remaining[i] -= current_toy
                        new_remaining_sorted = sorted(new_remaining, reverse=True)
                        if backtrack(index + 1, new_remaining_sorted):
                            memo[key] = True
                            return True
                memo[key] = False
                return False
            
            initial_remaining = boxes_sorted.copy()
            if backtrack(0, initial_remaining):
                print(k)
                return
    
    print(-1)

if __name__ == "__main__":
    main()