# -*- coding: utf-8 -*-

n = list(str(int(input())))
ans = 0

if n[0] == "1":
    for i in range(1,len(n)):
        if n[i] == "3":
            ans += 1
        else:
            print("-1")
            break
    else:
        if ans == 0:
            print(-1)
        else:
            print(ans)
else:
    print("-1")