def solution(A):
    numcouunt = []
    count = []
    for num in set(A):
        numcount.append(A.count(num))
        count.append(num)
    if numcount:
        if max(numcount) > len(A) / 2:
            num = count[numcount.index(max(numcount))]
            return A.index(num)
    return -1