def solution(s):
    answer = 0
    numbers = s.split()
    for i in range(len(numbers)):
        if numbers[i] == "Z":
            answer -= int(numbers[i-1])
        else:
            answer += int(numbers[i])
    return answer

def solution(array):
    answer = 0
    
    for i in array:
        answer += str(i).count(str(7))
    
    return answer