import sys

def main():
    str1 = input()
    sum = 0
    for i in range(len(str1)):
        if str1[i] == '0' or str1[i] == '6' or str1[i] == '9':
            sum += 1
        elif str1[i] == '8':
            sum += 2
        else:
            sum += 0
    print(sum)


if __name__ == "__main__":
    main()