import sys
from random import *
from itertools import permutations
from math import gcd
input = lambda: sys.stdin.readline().strip()


def mas():
    return list(map(int, input().split()))

for a in range(1, 1000):
    #один общий делитель != 1 <=> gcd != 1
    f = True
    for x in range(1, 1000):
        f1 = gcd(x, 42) != 1
        f2 = gcd(x, 7) != 1
        if (f1 <= (not(f2))) or (x + a >= 25):
            continue
        else:
            f = False
            break
    if f:
        print(a)
        break