Problem:
 Score : 100 points    Problem Statement On the Planet AtCoder, there are four types of bases: A , C , G and T . A bonds with T , and C bonds with G .  You are given a letter b as input, which is A , C , G or T . Write a program that prints the letter representing the base that bonds with the base b .      Constraints  b is one of the letters A , C , G and T .         Input Input is given from Standard Input in the following format:  b       Output Print the letter representing the base that bonds with the base b .        Sample Input 1 A      Sample Output 1 T       Sample Input 2 G      Sample Output 2 C

Solution (Python):
c = input()

if c == 'A':
  print('T')
if c == 'T':
  print('A')
if c == 'G':
  print('C')
if c == 'C':
  print('G')

Solution (Python):
dict={"A":"T","C":"G","T":"A","G":"C"}
print(dict[input()])

Solution (Python):
b = input()
if b == 'A':
    print("T")
if b == 'T':
    print("A")
if b == 'C':
    print("G")
if b == 'G':
    print("C")

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'G':
  print('C')
elif b == 'C':
  print('G')

Solution (Python):





b = input()

if b =='A':
    print('T')
elif b == 'C':
    print('G')
elif b == 'G':
    print('C')
else:
     print('A')

Solution (Python):
b=input()
    
if b=='A':
    print('T')
elif b=='T':
    print('A')
elif b=='C':
    print('G')
elif b=='G':
    print('C')

Solution (Python):
b = input()
if b == "A":
	print ("T")
elif b == "T":
	print ("A")
elif b == "G":
	print ("C")
else:
	print ("G")

Solution (Python):
import sys
input = sys.stdin.readline
dictionary = {"A":"T","T":"A","C":"G","G":"C"}
def print_ans(b):
    """Test Case
    >>> print_ans("A")
    T
    >>> print_ans("G")
    C
    """
    print(dictionary[b])


if __name__ == '__main__':
    b = input().rstrip()
    print_ans(b)

Solution (Python):
s = input()

if s=='A':
  print('T')
if s=='T':
  print('A')
if s=='G':
  print('C')
if s=='C':
  print('G')

Solution (Python):

import math
import datetime





b = str(input())

if b == "A" :
  print ("T")
elif b == "T" :
  print ("A")
elif b == "C" :
  print ("G")
elif b == "G" :
  print ("C")

Solution (Python):
x = input()
if x == "A":
  print("T")
elif x == "T":
  print("A")
elif x == "C":
  print("G")
else:
  print("C")

Solution (Python):
dic = {
        "A": "T",
        "T": "A",
        "C":"G",
         "G":"C"
        }
b = input()
print(dic[b])

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'C':
    print('G')
elif b == 'G':
    print('C')
elif b == 'T':
    print('A')

Solution (Python):
t1 = 'ACGT'
t2 = 'TGCA'

c = input()
i = t1.index(c)
print(t2[i])

Solution (Python):
Helix=input()
if Helix=='A':
    print ("T")
elif Helix=="T":
    print ("A")
elif Helix=="G":
    print ("C")
elif Helix=="C":
    print ("G")

Solution (Python):
import sys

bond = dict(zip('ATCG', 'TAGC'))

def main():
    b = sys.stdin.readline().rstrip()
    print(bond[b])

if __name__ == "__main__":
    main()

Solution (Python):
b=input()
dic={"A":"T","T":"A","C":"G","G":"C"}
print(dic[b])

Solution (Python):
b = input()
l = "ATCG"

if b == l[0]: print(l[1])
if b == l[1]: print(l[0])
if b == l[2]: print(l[3])
if b == l[3]: print(l[2])

Solution (Python):
print('ATCG'['TAGC'.find(input())])

Solution (Python):
b = input()
if b == "A":
  print("T")
elif b == "T":
  print("A")
elif b == "G":
  print("C")
elif b == "C":
  print("G")

Solution (Python):
print({"A": "T", "C": "G", "G": "C", "T": "A"}[input()])

Solution (Python):
b = input()
ans = ["0"]*len(b)
convert = {"A":"T","C":"G","G":"C","T":"A"}
for i in range(len(b)):
 	ans[i] = convert[b[i]]
for i in range(len(b)):
 	print(ans[i],end="")

Solution (Python):
b=input()

if b == "A":
  print("T")
elif b=="T":
  print("A")
elif b=="G":
  print("C")
elif b=="C":
  print("G")

Solution (Python):
b=input()
if b=='G':
  print('C')
elif b=='C':
  print('G')
elif b=='A':
  print('T')
else:
  print('A')

Solution (Python):
b = input()
if b == "A":
    print("T")
if b == "T":
    print("A")
if b == "C":
    print("G")
if b == "G":
    print("C")

Solution (Python):
b = input()

if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
elif b == "G":
    print("C")

Solution (Python):
b=input()
print("A" if b=="T" else "T" if b=="A" else "C" if b=="G" else "G")

Solution (Python):
b=input()
if b in "AT":print("T" if b=="A" else "A")
else:print("G" if b=="C" else "C")

Solution (Python):
b = input()

if(b=="A"):
    print("T")
elif(b=="T"):
    print("A")
elif(b=="C"):
    print("G")
else:
    print("C")

Solution (Python):
b = input()
list_one = ["A","T"]
list_two = ["C","G"]
if b in list_one:
    res = "".join(list_one).replace(b,"")
elif b in list_two:
    res = "".join(list_two).replace(b,"")
print(res)

Solution (Python):
print('TGCA'['ACGT'.index(input())])

Solution (Python):
b = input()

a = {"A":"T","T":"A","G":"C","C":"G"}
print(a[b])

Solution (Python):
b=input()
if b=='A':
  print('T')
elif b=='T':
  print('A')
elif b=='C':
  print('G')
else:
  print('C')

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'C':
    print('G')
elif b == ('T'):
    print('A')
else:
    print('C')

Solution (Python):
print({'A': 'T', 'T': 'A', 'G': 'C', 'C': 'G'}[input()])

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'C':
    print('G')
elif b == 'G':
    print('C')
else:
    print('A')

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'C':
  print('G')
else:
  print('C')

Solution (Python):

b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "G":
    print("C")
else:
    print("G")

Solution (Python):
b=input()
if b=="A":
  print("T")
elif b=="T":
  print("A")
elif b=="C":
  print("G")
elif b=="G":
  print("C")

Solution (Python):
a = input()

b = {"A":"T","T":"A","C":"G","G":"C"}
print ( b[a])

Solution (Python):
b = input()

if b == 'A':
  print ('T')
elif b == 'T':
  print ('A')
elif b == 'C':
  print ('G')
else:
  print('C')

Solution (Python):
s = input()
if(s=="A"): print("T")
if(s=="T"): print("A")
if(s=="C"): print("G")
if(s=="G"): print("C")

Solution (Python):
base_pairs = {"A":"T", "T":"A", "C":"G", "G":"C"}

base = input()
print(base_pairs[base])

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
else:
    print("C")

Solution (Python):

import sys










def main():
    b = sys.stdin.readline().rstrip()
    if b == 'A':
        ans = 'T'
    elif b == 'T':
        ans = 'A'
    elif b == 'G':
        ans = 'C'
    else:
        ans = 'G'
    
    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "C":
    print("G")
elif b == "G":
    print("C")
else:
    print("A")

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'C':
  print('G')
elif b == 'G':
  print('C')

Solution (Python):
b=str(input())
if b=="A":
  print("T")
elif b=="C":
  print("G")
elif b=="G":
  print("C")
else:
  print("A")

Solution (Python):
b = input()

if b == "A":
    print("T")
if b == "T":
    print("A")
    
if b == "C":
    print("G")
if b == "G":
    print("C")

Solution (Python):
b = input()

combination = {"A":"T" , "C":"G" , "G":"C" , "T":"A"}

print(combination[b])

Solution (Python):
b=input()

if b=="A":
  print("T")
elif b=="C":
  print("G")
elif b=="G":
  print("C")
elif b=="T":
  print("A")

Solution (Python):
s=input()
if s=="A":
    print("T")
elif s=="T":
    print("A")
elif s=="C":
    print("G")
else:
    print("C")

Solution (Python):
b =str(input())
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
elif b == "G":
    print("C")

Solution (Python):

b = input()

dic = {"A":"T","C":"G","G":"C","T":"A"}

ret = dic[b]


print(ret)

Solution (Python):
b=input()
if b=='A':
    X='T'
elif b=='T':
    X='A'
elif b=='C':
    X='G'
else:
    X='C'
print(X)

Solution (Python):
n = input()

if n == 'A':
  print('T')
  
elif n == 'T':
  print('A')
  
elif n == 'C':
  print('G')
  
elif n == 'G':
  print('C')

Solution (Python):
b = input()

if b == "A":
    print("T")
elif b== "T":
    print("A")
elif b == "C":
    print("G")
elif b == "G":
    print("C")

Solution (Python):
N=input()

a={"A":"T","G":"C","T":"A","C":"G"}
print(a[N])

Solution (Python):
base_list = ['A','C','G','T']
base = str(input())

if base == 'A':
  print('T')
elif base == 'C':
  print('G')
elif base == 'G':
  print('C')
elif base == 'T':
  print('A')

Solution (Python):

bonds_pairs = [['A', 'T'], ['C', 'G']]
b = input()
for pairs in bonds_pairs:
    if b in pairs:
        print(pairs[1 - pairs.index(b)])
        break

Solution (Python):
b = input()
c = {"A":"T", "T":"A", "G":"C", "C":"G"}
print(c[b])

Solution (Python):
s = input()
if s=="A":
  print("T")
elif s=="T":
  print("A")
elif s=="G":
  print("C")
else:
  print("G")

Solution (Python):
def main():
    b = input()
    array = ['A','C','G','T']
    if b == array[0]:
        print(array[3])
    if b == array[1]:
        print(array[2])
    if b == array[2]:
        print(array[1])
    if b == array[3]:
        print(array[0])

if __name__ == '__main__':
    main()

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'G':
  print('C')
elif b == 'C':
  print('G')

Solution (Python):
b =str(input())
if b=='A':
  print('T')
elif b=='C':
  print('G')
elif b=='G':
  print('C')
elif b=='T':
  print('A')

Solution (Python):
s = input()

if s == "A":
    print("T")
elif s == "T":
    print("A")
elif s == "C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()
if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'G':
    print('C')
else:
    print('G')

Solution (Python):
b = input();

if b == "A": print("T")
if b == "T": print("A")
if b == "G": print("C")
if b == "C": print("G")

Solution (Python):
b = input()
if b == "A":
  print("T")
elif b == "C":
  print("G")
elif b == "G":
  print("C")
elif b == "T":
  print("A")

Solution (Python):
b = input()
s = {"A": "T", "C": "G", "G": "C", "T": "A"}

print(s[b])

Solution (Python):
d = {'A':'T','T':'A','C':'G','G':'C'}
b=input()
print(d[b])

Solution (Python):
from sys import stdin

s = stdin.readline().rstrip()

li = ["A","T"]
li2 = ["C","G"]

if s in li:
    li.pop(li.index(s))
    print(li[0])
else:
    li2.pop(li2.index(s))
    print(li2[0])

Solution (Python):
b = input()
if b in ["A", "T"]:
    print(["A", "T"][["A", "T"].index(b) - 1])
else:
    print(["G", "C"][["G", "C"].index(b) - 1])

Solution (Python):
b = input()
B = ["A","G","C","T"]
B_rev = ["T","C","G","A"]
print(B_rev[B.index(b)])

Solution (Python):
b=input('')
if b=='A':
    print('T')
elif b=='T':
    print('A')
elif b=='G':
    print('C')
elif b=='C':
    print('G')

Solution (Python):
b = input()
d = {'A':'T', 'T':'A', 'G':'C', 'C':'G'}
print(d[b])

Solution (Python):
n = input()

e = {'A' : 'T', 'T' : 'A', 'C' : 'G', 'G' : 'C'}
print(e[n])

Solution (Python):
b = input()

if b == 'C':
  print('G')
elif b == 'G':
  print('C')
  
elif b == 'T':
  print('A')

elif b == 'A':
  print('T')

Solution (Python):
S = "ACGT"
T = "TGCA"

b = input()
print(T[S.index(b)])

Solution (Python):
b=input()
if b=='A':
    print('T')
elif b=='C':
    print('G')
elif b=='T':
    print('A')
else:
    print('C')

Solution (Python):
B = input()

if B == 'A':
    print('T')
elif B == 'T':
    print('A')
elif B == 'C':
    print('G')
else:
    print('C')

Solution (Python):
print("".join([{'A':'T','T':'A','C':'G','G':'C'}[i] for i in input()]))

Solution (Python):
print("ATCG"["TAGC".find(input())])

Solution (Python):
b=input()
x=["A","T"]
y=["C","G"]

if b in x:
    x.remove(b)
    print(x[0])
else:
    y.remove(b)
    print(y[0])

Solution (Python):
b=input()

if b=='A' :
    ans='T'
elif b=='T' :
    ans='A'
elif b=='C' :
    ans='G'
else :
    ans='C'
print(ans)

Solution (Python):
b=input()
if b=='A':
    print('T')
elif b=='T':
    print('A')
elif b=='C':
    print('G')
else:
    print('C')

Solution (Python):
b = input()
if b == "A": print("T")
elif b == "T": print("A")
elif b == "G": print("C")
else: print("G")

Solution (Python):
b = str(input())

if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'G':
    print('C')
else:
    print('G')

Solution (Python):
b = input()
if b == 'A':
	print('T')
if b == 'T':
	print('A')
if b == 'G':
	print('C')
if b == 'C':
	print('G')

Solution (Python):
x=input()
if x=='A':
    print('T')
elif x=='T':
    print('A')
elif x=='G':
    print('C')
elif x=='C':
    print('G')

Solution (Python):
b = input()
if b == "A":
  print("T")
elif b == "T":
  print("A")
elif b == "C":
  print("G")
else:
  print("C")

Solution (Python):
b = input()
d = {'A': 'T', 'T': 'A', 'C': 'G', 'G': 'C'}
print(d[b])

Solution (Python):
b = str(input())

di= {'A':'T', 'T':'A', 'G':'C', 'C':'G'}

print(di[b])

Solution (Python):
s = input()

if s == "A":
    print("T")
elif s == "T":
    print("A")
elif s =="C":
    print("G")
else:
    print("C")

Solution (Python):


def main():
    b = input()
    dict = {
        'A':'T',
        'T':'A',
        'C':'G',
        'G':'C'
    }
    print(dict[b])

if __name__ == "__main__":
    main()

Solution (Python):
b = input()
print('A' if b=='T' else 'T' if b=='A' else 'C' if b=='G' else 'G')

Solution (Python):
n=str(input())
print("T" if n=="A" else "G" if n=="C" else "C" if n=="G" else "A")

Solution (Python):
b = input()
print('A' if b == 'T' else 'T' if b == 'A' else 'G' if b == 'C' else 'C')

Solution (Python):
b=str(input())

if b=='A':
	print('T')
	
elif b=='T':
	print('A')
	
elif b=='C':
	print('G')
	
else:
	print('C')

Solution (Python):
b=str(input())
if b=='A' :
    print('T')
elif b=='T' :
    print('A')
elif b=='G' :
    print('C')
else  :
    print('G')

Solution (Python):
b = input()

if b == "A":
  print("T")
elif b == "C":
  print("G")
elif b == "G":
  print("C")
else:
  print("A")

Solution (Python):
s = input()
if s == "A":
    print("T")
elif s == "T":
    print("A")
elif s == "C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()
s = ["A" , "C" , "G" , "T"]

for i in range(4):
    if s[i] == b:
        print(s[3 - i])

Solution (Python):
b = input()
if b == "A":
    print("T")
if b == "C":
    print("G")
if b == "G":
    print("C")
if b == "T":
    print("A")

Solution (Python):
b=input()
print("T" if b=="A" else "A" if b=="T" else "G" if b=="C" else "C")

Solution (Python):
b = str(input())
table = b.maketrans({'A':'T','C':'G','T':'A','G':'C'})
print(b.translate(table))

Solution (Python):
b=input()
if b=='A':
	print('T')
if b=='T':
	print('A')
if b=='C':
	print('G')
if b=='G':
	print('C')

Solution (Python):
s = input()

if s == 'A':
  print('T')
elif s == 'T':
  print('A')
elif s == 'C':
  print('G')
else:
  print('C')

Solution (Python):
b=input()
H={'A':'T','C':'G','T':'A','G':'C'}
print(H[b])

Solution (Python):
print({'A': 'T', 'T': 'A', 'C': 'G', 'G': 'C'}[input()])

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    d = {"A": "T", "T": "A", "C": "G", "G": "C"}
    s = str(input().rstrip('\n'))
    print(d[s])


if __name__ == '__main__':
    slove()

Solution (Python):
a = input()
print("AT".replace(a,"") if a in "AT" else "GC".replace(a,""))

Solution (Python):
d = {"A":"T","T":"A","G":"C","C":"G"}
print(d[input()])

Solution (Python):
x = input()

if x == "A":
  print("T")
elif x == "T":
  print("A")
elif x == "G":
  print("C")
else:
  print("G")

Solution (Python):
b = input()
c = {'A':'T', 'T':'A', 'C':'G', 'G':'C'}
print(c[b])

Solution (Python):
b = input()
if b == "A":
	print("T")
elif b == "T":
	print("A")
elif b == "C":
	print("G")
elif b == "G":
	print("C")

Solution (Python):
b=input()
if b=='A':c='T'
if b=='T':c='A'
if b=='C':c='G'
if b=='G':c='C'
print(c)

Solution (Python):
b=str(input())
if b=='A':
  print('T')
elif b=='T':
  print('A')
elif b=='G':
  print('C')
else:
  print('G')

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'T' :
    print('A')
elif b == 'G' :
    print('C')
elif b == 'C' :
    print('G')

Solution (Python):
b = str(input())
base = {'A':'T','T':'A','C':'G','G':'C'} 
print(base[b])

Solution (Python):
b=input()
if b=='A':
  print('T')
elif b=='T':
  print('A')
elif b=='G':
  print('C')
else:
  print('G')

Solution (Python):
b = input()

if b == 'A':
  print('T')
if b == 'T':
  print('A')
if b == 'C':
  print('G')
if b == 'G':
  print('C')

Solution (Python):
b = input()

if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'C':
  print('G')
else:
  print('C')

Solution (Python):
b = input()
bd = {"A": "T", "C": "G", "G": "C", "T": "A"}

print(bd[b])

Solution (Python):
b = list(input())
ans = list()
for i in range(len(b)):
    if b[i] == "A":
        ans.append("T")
    elif b[i] == "T":
        ans.append("A")
    elif b[i] == "C":
        ans.append("G")
    else:
        ans.append("C")
print("".join(ans))

Solution (Python):
s = input()
if s=="A": print("T")
if s=="T": print("A")
if s=="G": print("C")
if s=="C": print("G")

Solution (Python):
b=input()
print("A" if b=="T" else "T" if b=="A" else "C" if b=="G" else "G")

Solution (Python):
S = input()
if S == 'A':
    print('T')
if S == 'C':
    print('G')
if S == 'G':
    print('C')
if S == 'T':
    print('A')

Solution (Python):
b=input()

if b=='A':
    print('T')
elif b=='T':
    print('A')
elif b=='C':
    print('G')
else:
    print('C')

Solution (Python):
s = input()
if s == "A":
  print("T")
elif s == "T":
  print("A")
elif s == "C":
  print("G")
elif s == "G":
  print("C")

Solution (Python):
s=input()
if s=='A':
  print('T')
elif s=='T':
  print('A')
elif s=='C':
  print('G')
else:
  print('C')

Solution (Python):
b=input()

if b=='A':
  print('T')
elif b=='T':
  print('A')
elif b=='C':
  print('G')
elif b=='G':
  print('C')

Solution (Python):
s=input()
if s=='A':
  print('T')
elif s=='T':
  print('A')
elif s=='C':
  print('G')
else:
  print('C')

Solution (Python):
b = input()
print("A" if b=="T" else "T" if b=="A" else "C" if b=="G" else "G")

Solution (Python):
b = input()
a, c = "AT", "CG"
print(a.strip(b)) if b in a else print(c.strip(b))

Solution (Python):
s = input()
if s =='A':
  print('T')
elif s =='T':
  print('A')
elif s =='G':
  print('C')
elif s =='C':
  print('G')

Solution (Python):
n = input()
if n == "A":
         print("T")
elif n == "T":
         print("A")
elif n == "G":
         print("C")
else:
         print("G")

Solution (Python):
b = input()

if b == 'T':
  print('A')
if b == 'G':
  print('C')
if b == 'A':
  print('T')
if b == 'C':
  print('G')

Solution (Python):
b= input()
if b == "A":
    print("T")
if b == "T":
    print("A")
if b == "G":
    print("C")
if b == "C":
    print("G")

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "C":
    print("G")
elif b == "G":
    print("C")
elif b == "T":
    print("A")

Solution (Python):
s = input()

if s == 'A':
    print('T')
elif s == 'T':
    print('A')
elif s == 'C':
    print('G')
else:
    print('C')

Solution (Python):
'''A - Double Helix
https://atcoder.jp/contests/abc122/tasks/abc122_a

>>> main('A')
T
>>> main('G')
C
'''


def main(b):
    if b == 'A':
        print('T')
    elif b =='T':
        print('A')
    elif b == 'G':
        print('C')
    elif b == 'C':
        print('G')


if __name__ == '__main__':
    main(input())

Solution (Python):
s=input()
if s == 'A':
  print('T')
elif s == 'T':
  print('A')
elif s == 'G':
  print('C')
elif s == 'C':
  print('G')

Solution (Python):
b = input()
if b == 'A':
    print('T')
if b == 'T':
    print('A')
if b == 'C':
    print('G')
if b == 'G':
    print('C')

Solution (Python):
b = input()
if b == 'A':
    print('T')
elif b == 'C':
    print('G')
elif b == 'G':
    print('C')
else:
    print('A')

Solution (Python):
B = input()
print('A' if B == 'T' else 'T' if B == 'A' else 'C' if B == 'G' else 'G')

Solution (Python):
print("TAGC"["ATCG".index(input())])

Solution (Python):
b = input()

at,gc = "AT","GC"

if b in at:
    print(at.replace(b, ""))
else:
    print(gc.replace(b, ""))

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    d = {"A": "T", "T": "A", "C": "G", "G": "C"}
    b = str(input().rstrip('\n'))
    print(d[b])


if __name__ == '__main__':
    slove()

Solution (Python):
print("TAGC"["ATCG".index(input())])

Solution (Python):
b = input()
a = ["A", "T"]
c = ["C", "G"]
if b is a[0]:
  print(a[1])
if b is a[1]:
  print(a[0])
if b is c[0]:
  print(c[1])
if b is c[1]:
  print(c[0])

Solution (Python):
b = input()
D = {'A': 'T', 'T': 'A', 'C': 'G', 'G': 'C'}
print(D[b])

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'C':
    print('G')
elif b == 'G':
    print('C')
elif b == 'T':
    print('A')

Solution (Python):
b = input()
print('A' if b=='T' else 'T' if b=='A' else 'C' if b=='G' else 'G')

Solution (Python):
print("TGCA"["ACGT".index(input())])

Solution (Python):
b=input()
if b=="A":
  print("T")
elif b=="T":
  print("A")
elif b=="G":
  print("C")
else:
  print("G")

Solution (Python):
b = input()
if b == 'A' or b == 'T':
    print('AT'.replace(b, ''))
elif b == 'C' or b == 'G':
    print('CG'.replace(b, ''))

Solution (Python):
S = [['A','C','G','T'],['T','G','C','A']]
print(S[1][S[0].index(input())])

Solution (Python):
b = input()
c = {'A': 'T', 'T': 'A', 'C': 'G', 'G': 'C'}
print(c[b])

Solution (Python):
b = input()
if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'G':
    print('C')
else:
    print('G')

Solution (Python):
b = input()
if b=='A':
  print('T')
elif b=='T':
  print('A')
elif b=='G':
  print('C')
else:
  print('G')

Solution (Python):
X=input()
if X=="A":
  print("T")
elif X=="T":
  print("A")
elif X=="G":
  print("C")
else:
  print("G")

Solution (Python):
pairs = {'A':'T', 'T':'A','G':'C','C':'G'}
s = input()
print(pairs[s.upper()])

Solution (Python):
b = input()
print("A" if b == "T" else "T" if b == "A" else "G" if b == "C" else "C")

Solution (Python):
b = input()

l1 = {"A":"T","T":"A"}
l2 = {"C":"G","G":"C"}

ans = None

if b in l1:
  ans = l1[b]
else:
  ans = l2[b]
  
print(ans)

Solution (Python):
b=input()
if b=="A":
  print("T")
elif b=="C":
  print("G")
elif b=="T":
  print("A")
else:
  print("C")

Solution (Python):
b = input()

if(b == 'A'):
    print('T')
if(b == 'T'):
    print('A')
if(b == 'G'):
    print('C')
if(b == 'C'):
    print('G')

Solution (Python):
b = input()
if b=='A':print('T')
elif b=='T':print('A')
elif b=='C':print('G')
elif b=='G':print('C')

Solution (Python):
x = input()
if x == "A":
  print("T")
elif x == "T":
  print("A")
elif x == "G":
  print("C")
elif x == "C":
  print("G")

Solution (Python):
b = input()

if b == 'T':
  print('A')
elif b == 'A':
  print('T')
elif b == 'G':
  print('C')
elif b == 'C':
  print('G')

Solution (Python):
s=input()
dic = {"A": "T", "T": "A", "G": "C", "C":"G"}
print(dic[s])

Solution (Python):
b = input()

if b in {'A', 'T'}:
    print(*({'A', 'T'} - {b}))
elif b in {'C', 'G'}:
    print(*({'C', 'G'} - {b}))

Solution (Python):
b=input()

if b == 'A':
    print('T')
    
elif b == 'C':
    print('G')
    
elif b == 'G':
    print('C')
    
else:
    print('A')

Solution (Python):
n=input()

if n==("A"):
  print("T")
elif n==("C"):
  print("G")
elif n==("G"):
  print("C")
else:
  print("A")

Solution (Python):
b=list(input())
t=[]
for i in range(len(b)):
    if b[i]=='A':
        t+=['T']
    elif b[i]=='T':
        t+=['A']
    elif b[i]=='G':
        t+=['C']
    elif b[i]=='C':
        t+=['G']
t=''.join(t)
print(t)

Solution (Python):
base = {"A": "T", "C": "G", "G": "C", "T": "A"}
print(base[input()])

Solution (Python):
b = input()

if b == "A":
  print("T")
elif b == "T":
  print("A")
elif b == "C":
  print("G")
else:
  print("C")

Solution (Python):
b = input()
out = ""

if b == "A":
    out = "T"
elif b == "C":
    out = "G"
elif b == "G":
    out = "C"
else:
    out = "A"
print(out)

Solution (Python):
b = input()

if b == "A":
    print("T")
elif b == "C":
    print("G")
elif b == "T":
    print("A")
elif b == "G":
    print("C")

Solution (Python):
b = str(input())
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'C':
  print('G')
elif b == 'G':
  print('C')

Solution (Python):
b = (input())
if b == "A":
    print("T")
elif b == "C":
    print("G")
elif b == "T":
    print("A")
else:
    print("C")

Solution (Python):


b= str(input())
if b == 'A':
	print('T')
elif b =='T':
	print('A')
elif b == 'C':
	print('G')
else:
	print('C')

Solution (Python):

b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()
if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'G':
    print('C')
elif b == 'C':
    print('G')

Solution (Python):
b=input()
print('A' if b=='T' else 'T' if b=='A' else 'C' if b=='G' else 'G')

Solution (Python):

s = input()
if s == 'A':
  print('T')
elif s == 'T':
  print('A')
elif s == 'C':
  print('G')
else:
  print('C')

Solution (Python):
import sys

if sys.platform =='ios':
    sys.stdin=open('input_file.txt')
    
b=input()

if b=="A":
	print("T")
if b=="T":
	print("A")
if b=="G":
	print("C")
if b=="C":
	print("G")

Solution (Python):
b=input()
print("A" if b=="T" else "T" if b=="A" else "C" if b=="G" else "G")

Solution (Python):
S = input()
if S == 'A':
    print('T')
elif S == 'T':
    print('A')
elif S == 'C':
    print('G')
elif S == 'G':
    print('C')

Solution (Python):
b=str(input())
if b=='A':
    print('T')
elif b=='T':
    print('A')
elif b=='G':
    print('C')
else:
    print('G')

Solution (Python):
b = input()
print('A' if b == 'T' else 'T' if b == 'A' else 'C' if b == 'G' else 'G')

Solution (Python):
b = input()
if b == 'A':
    print('T')
if b == 'T':
    print('A')
if b == 'C':
    print('G')
if b == 'G':
    print('C')

Solution (Python):
s = input()
if s == "A":
  print("T")
elif s == "C":
  print("G")
elif s == "G":
  print("C")
else:
  print("A")

Solution (Python):
a = {t[0]:t[1] for t in zip(list("ATCG"), list("TAGC"))}
print(a[input()])

Solution (Python):
b=input()
print('A' if b=='T' else 'C' if b=='G' else 'G' if b=='C' else 'T')

Solution (Python):
b = input()
c = {"A":"T","C":"G" ,"T":"A","G":"C"}
print(c[b])

Solution (Python):
b = input()
print("A" if b == "T" else "T" if b == "A" else "C" if b == "G" else "G")

Solution (Python):
b = input()

print('A' if b == 'T' else 'T' if b == 'A' else 'C' if b == 'G' else 'G')

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
elif b == "G":
    print("C")

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'G':
  print('C')
else:
  print('G')

Solution (Python):
d =dict(A="T",T="A",C="G",G="C")
print(d[input()])

Solution (Python):
b = {"A":"T", "T":"A", "C":"G", "G":"C"}
print (b[input()])

Solution (Python):
print("ATCG"["TAGC".find(input())])

Solution (Python):
b = input()

if b =='A':
    print('T')
if b =='T':
    print('A')
if b =='G':
    print('C')
if b =='C':
    print('G')

Solution (Python):
n=input()
if n=='A':
  print('T')
elif n=='T':
  print('A')
elif n=='C':
  print('G')
else:
  print('C')

Solution (Python):
b = input()

if b == "A":
    print("T")
elif b == "C":
    print("G")
elif b == "G":
    print("C")
else:
    print("A")

Solution (Python):
b = input().strip()
x = ""
for i in range(len(b)):
    if b[i]=="A":
        x += "T"
    elif b[i]=="T":
        x += "A"
    elif b[i]=="C":
        x += "G"
    elif b[i]=="G":
        x += "C"
print(x)

Solution (Python):
b=input()
if b=='A':
  print('T')
if b=='T':
  print('A')
if b=='C':
  print('G')
if b=='G':
  print('C')

Solution (Python):
b = input()

if (b=="A"):
    print("T")
elif b=="T":
    print("A")
elif b=="C":
    print("G")
else:
    print("C")

Solution (Python):
b = input()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "G":
    print("C")
else:
    print("G")

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'C':
    print('G')
else:
    print('C')

Solution (Python):
x  = input()
if x=="T":
  print("A")
elif x=="A":
  print("T")
elif  x=="C":
  print("G")
else:
  print("C")

Solution (Python):
def makelist(n, m):
    return [[0 for i in range(m)] for j in range(n)]

d = { "A": "T", "T": "A", "C": "G", "G": "C" }
b = input()
ans = d[b]
print(ans)

Solution (Python):
n = input()

if n == 'A':
    print('T')
elif n == 'T':
    print('A')
elif n == 'C':
    print('G')
else:
    print('C')

Solution (Python):
b=input()
if b=="A":
    print("T")
elif b=="T":
    print("A")
elif b=="C":
    print("G")
elif b=="G":
    print("C")

Solution (Python):
b=input()
if b=="A":
  print("T")
elif b=="T":
  print("A")
elif b=="G":
  print("C")
else:
  print("G")

Solution (Python):
b=input()

if b=="A":
    print("T")
elif b=="T":
    print("A")
elif b=="G":
    print("C")
else:
    print("G")

Solution (Python):
b = input()
if b=="A":
  print("T")
elif b=="T":
  print("A")
elif b=="G":
  print("C")
else :
  print("G")

Solution (Python):
b = input()
d = {"A": "T", "C": "G", "G": "C", "T": "A", }
print(d[b])

Solution (Python):
b=input()
data1=['A','T']
data2=['C','G']
if b in data1:
    print(data1[data1.index(b)-1])
if b in data2:
    print(data2[data2.index(b)-1])

Solution (Python):
b=input()
c={'A':'T', 'T':'A', 'G':'C', 'C':'G'}
print(c[b])

Solution (Python):
b = input()
c = {'A':'T', 'T':'A', 'G':'C', 'C':'G'}
print(c[b])

Solution (Python):
s = input()
print(s.translate(str.maketrans({"A":"T","T":"A","C":"G","G":"C"})))

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'T':
  print('A')
elif b == 'C':
  print('G')
else:
  print('C')

Solution (Python):
b = input()
if b == 'A':
  print('T')
elif b == 'C':
  print('G')
elif b == 'G':
  print('C')
elif b == 'T':
  print('A')

Solution (Python):
b=input()
print('A' if b=='T'
      else 'T' if b=='A'
      else 'G' if b=='C'
      else 'C')

Solution (Python):
d={
  "A":"T",
  "T":"A",
  "C":"G",
  "G":"C"
}
b=input()
print(d[b])

Solution (Python):
b = input()
dic = {'A': 'T', 'T': 'A', 'G':'C', 'C':'G'}
print(dic[b])

Solution (Python):
b = input()
dic = {"A":"T", "C":"G", "G":"C", "T":"A"}
print(dic[b])

Solution (Python):
b = input()

if b =="A":
  print("T")
elif b =="T":
  print("A")
elif b =="G":
  print("C")
else: print("G")

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == "C":
    print('G')
else:
    print('C')

Solution (Python):
b = input()

if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'C':
    print('G')
else:
    print('C')

Solution (Python):
s=input()

if s=='A':
  print('T')
elif s=='T':
  print('A')
elif s=='G':
  print('C')
elif s=='C':
  print('G')

Solution (Python):
b=input()
d={'A':'T','T':'A','C':'G','G':'C'}
print(d[b])

Solution (Python):
if __name__ == '__main__':
    B = str(input())
    A = ''
    for b in B:
        if b =='A':
            A += 'T'
        elif b == 'T':
            A += 'A'
        elif b == 'C':
            A += 'G'
        elif b =='G':
            A += 'C'
            
    print(A)

Solution (Python):
b = input()
d = {'A' : 'T', 'T' : 'A', 'C' : 'G', 'G' : 'C'}
print(d[b])

Solution (Python):
b = input()

ans = ''
if b == 'A':
  ans = 'T'
if b == 'T':
  ans = 'A'
if b == 'C':
  ans = 'G'
if b == 'G':
  ans = 'C'
print(ans)