import sys

import itertools

sys.setrecursionlimit(1000000000)

from heapq import heapify,heappop,heappush,heappushpop

import math

import collections

import copy

INF = 10**18





if __name__ == "__main__":

    x = int(eval(input()))

    if x>=30:

        print("Yes")

    else:

        print("No")
x = int(eval(input()))

if x>=30:

  print("Yes")

else:

  print("No")
import sys
import itertools

sys.setrecursionlimit(1000000000)
from heapq import heapify, heappop, heappush, heappushpop
import math
import collections
import copy

INF = 10**18
if __name__ == "__main__":
    x = int(eval(input()))
    if x >= 30:
        print("Yes")
    else:
        print("No")

x = int(eval(input()))
if x >= 30:
    print("Yes")
else:
    print("No")

-import sys -import itertools - -sys.setrecursionlimit(1000000000) -from heapq import heapify, heappop, heappush, heappushpop -import math -import collections -import copy - -INF = 10**18 -if __name__ == "__main__": -    x = int(eval(input())) -    if x >= 30: -        print("Yes") -    else: -        print("No") +x = int(eval(input())) +if x >= 30: +    print("Yes") +else: +    print("No")