https://programmers.co.kr/learn/courses/30/lessons/12901
def solution(a, b):
answer = ''
x=[31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
d=["FRI","SAT","SUN", "MON","TUE","WED","THU"]
s=-1
for i in range(a-1):
s+=x[i]
s+=b
s=s%7
answer=d[s]
return answer