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):
b=str(input())
if b=="T":
  b="A"
elif b=="A":
  b="T"
elif b=="G":
  b="C"
elif b=="C":
  b="G"
print(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):
b=input()
a=''
n=len(b)
for i in range(n):
  if b[i] == 'A':
    a += 'T'
  elif b[i] == 'T':
    a += 'A'
  elif b[i] == 'C':
    a += 'G'
  else:
    a += 'C'

print(a)

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

Solution (Python):
b = input()
print('T' if b=='A' else 'A' if b=='T' else '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()
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()
ans,pair = ['A','C','G','T'],['T','G','C','A']
for i,j in zip(ans,pair):
    if j == b:
        print(i)

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 = str(input())
s = ["A", "C", "G", "T"]
i = s.index(b)
print(s[-i -1])

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

Solution (Python):
a='A','C','G','T'
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 == "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().strip()
if b == 'A':
    print('T')
elif b == 'T':
    print('A')
elif b == 'C':
    print('G')
else:
    print('C')

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

Solution (Python):
b = input()

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

print(dic[b])

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

Solution (Python):
a = input()

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

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

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=="G":
  print("C")
elif b=="C":
  print("G")

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

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

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):
a="ACTGACT";print(a[a.index(input())+2])

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

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

Solution (Python):
import sys
input=sys.stdin.readline

def main():
    b = input().strip()
    if b == "A":
        print("T")
    elif b == "T":
        print("A")
    elif b == "G":
        print("C")
    else:
        print("G")

if __name__ == '__main__':
    main()

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 == "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()
print('ACGT'[-('ACGT'.index(B)+1)])

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()
acid = {'A':'T','C':'G','G':'C','T':'A'}
print(acid[b])

Solution (Python):
print("ATACGC"["ATACGC".find(str(input()))+1])

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

Solution (Python):
a='ACGT'
print(a[3-a.find(input())])

Solution (Python):
b=input()
A=['A','C','T','G']
j=[i for i in range(4) if A[i]==b]
print(A[j[0]-2])

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 == "T":
  print("A")
elif b == "A":
  print("T")
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):
def main():
    b = input()

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

main()

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

Solution (Python):
enki1 = ['A', 'C']
enki2 = ['T', 'G']
b = input()
if b in enki1:
    index = enki1.index(b)
    print(enki2[index])
else:
    index = enki2.index(b)
    print(enki1[index])

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 == "C":
    print("G")
else:
    print("C")

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")
elif b == "G" :
	print("C")

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

print(ans)

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

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

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

Solution (Python):


def main():
    b = input()

    if b == 'A':
        return 'T'
    elif b == 'T':
        return 'A'
    elif b == 'G':
        return 'C'
    elif b == 'C':
        return 'G'

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

Solution (Python):
b = input()

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

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

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

Solution (Python):
def func():
    b = input()

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


if __name__ == '__main__':
    func()

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

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

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=="C":
  print("G")
elif b=="G":
  print("C")

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()
a = ''
for i in range(len(b)):
    if b[i] == 'A':
        a += 'T'
    elif b[i] == 'T':
        a += 'A'
    elif b[i] == 'C':
        a += 'G'
    elif b[i] == 'G':
        a += 'C'
print(a)

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

Solution (Python):
import sys
input = sys.stdin.readline

s=input().split()
if s[0]=="A":
    print("T")
if s[0]=="T":
    print("A")
if s[0]=="C":
    print("G")
if s[0]=="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()
dic = {'A': 'T', 'T': 'A', 'G': 'C', 'C': 'G'}
print(dic[b])

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

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

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

print(twi[b])

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

Solution (Python):
b = input()

if b == 'A':
    b = 'T'
elif b == 'C':
    b = 'G'
elif b == 'T':
    b = 'A'
elif b == 'G':
    b = 'C'

print(b)

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

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

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

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

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

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

Solution (Python):
a = "ACGT"
print(a[3-a.find(input())])

Solution (Python):
N = input()
a = ['A','C','G','T']
for i in range(4):
	if a[i] == N:
		print(a[3-i])
		break

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

Solution (Python):
b=input()
enki_dict={'A':'T',
           'T':'A',
           'C':'G',
           'G':'C'}
print(enki_dict[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()
prine = ['A', 'T']
primidine = ['G', 'C']
print(prine[b == 'A'] if b in prine else primidine[b == 'G'])

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

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

Solution (Python):
print("".join("TGCA"["ACGT".find(c)]for c in input()))

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

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

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

Solution (Python):
import sys
input=sys.stdin.readline().strip

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

Solution (Python):
import sys

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

Solution (Python):
a = input()

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

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

Solution (Python):
N=input()
N={N}
G1={'A','T'}
G2={'C','G'}
print(*G1-N if N<G1 else G2-N)

Solution (Python):
dict = ["A", "C", "T","G" ]
s = input()
index = dict.index(s)
index = (index+2)%4
print(dict[index])

Solution (Python):
b=input()

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

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

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 in ["A", "T"]:
    print("T" if b == "A" else "A")
else:
    print("C" if b == "G" else "G")

Solution (Python):
b = input().split()[0]
enki_dict = dict(A='T', T='A', C='G', G='C')

print(enki_dict[b])

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):
b=input()
if "A" == b:
  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=="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):
d = {"A":"T","T":"A","C":"G","G":"C"}
print(d[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):
s = input()
if s == 'A':
    print('T')
elif s == 'T':
    print('A')
elif s == 'C':
    print('G')
else:
    print('C')

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

Solution (Python):
b = input()

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

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

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

Solution (Python):
a = input()

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

Solution (Python):
b=input()
print("T" if b=="A" else "A" if b=="T" 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')
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):
y = input()
stg = "ATCG"

for i in range(len(stg)):
	x = stg[i]
	if x == y:
		print(stg[i + (-1) ** i])
		break

Solution (Python):

b=str(input())
X={"A":"T","T":"A","C":"G","G":"C"}
print(X[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()

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

print(dic[b])

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

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

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

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

Solution (Python):
b=input()

type=["A","T","G","C"]

if b == type[0]:
    print(type[1])
elif b==type[1]:
    print(type[0])
elif b==type[2]:
    print(type[3])
else:
    print(type[2])

Solution (Python):
import math





inputa = input()













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

ans = dic[str(inputa[0])]
print(ans)

Solution (Python):
b=input()
print("AT"[b=="A"] if b=="A" or b=="T" else "CG"[b=="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==("A"):
  print("T")
elif b==('T'):
  print("A")
elif b==('G'):
  print("C")
else:
  print('G')

Solution (Python):
def test():
    enki = ["A","C","G","T"]

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


if __name__ == "__main__":
    test()

Solution (Python):
b = input()

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

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


if __name__ == "__main__":
    print(solve())

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):
s = input()

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

list1 = ['A', 'T', 'C', 'G']
list2 = ['T', 'A', 'G', 'C']

index = list1.index(b)

print(list2[index])

Solution (Python):
b=input()

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

if b=='C':
    print('G')
elif b=='G':
    print('C')

Solution (Python):
b = input()

helix = [['A','T'],['T','A'],['C','G'],['G','C']]

for i in range(4):
    if b == helix[i][0]:
        print(helix[i][1])
        break

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

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()
if b in ["A","T"]:
    print("A" if b=="T" else "T")
else:
    print("C" if b=="G" else "G")

Solution (Python):
S = input()

B =["A", "C", "G", "T"]
for i in range(1,len(B)+1):
  
  if B[i-1]==S:
    print(B[-i])

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

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

Solution (Python):
temp=input()

if temp=='A':
  print('T')
elif temp=='T':
  print('A')
elif temp=='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()
enkitsui = {'A':'T','C':'G','T':'A','G':'C'}
print(enkitsui[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")
elif b == "C":
  print("G")

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

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):
def main(b):
  if b in {'A', 'T'}:
    print('A') if b == 'T' else print('T')
  elif b in {'C', 'G'}:
    print('C') if b == 'G' else print('G')

main(input())

Solution (Python):

b = input()
en = {
    'A': 'T',
    'C': 'G',
    'T': 'A',
    'G': 'C',
}
print(en[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")
elif 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):
a = input()
if a == 'A':
  print("T")
elif a == 'T':
  print("A")
elif a == 'G':
  print("C")
else:
  print("G")

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):
d = {
  'A': 'T',
  'T': 'A',
  'C': 'G',
  'G': 'C'
}
print(d[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')
else:
    print('G')

Solution (Python):
"""
n = int(sys.stdin.readline())
a, b = map(int, sys.stdin.readline().split())
c = list(map(int, sys.stdin.readline().split()))
s = [list(map(int,list(sys.stdin.readline()))) for i in range(h)]  

a = 100
b = 0.987654321
print('{0:06d}-{1:6f}'.format(a,b))  
000100-0.987654


char_list = list("abcd") 
"""

import math
import sys
import itertools
import queue
from fractions import gcd

def lcm(a, b):
    return a * b // gcd(a, b)


mod = 1000000007

if __name__ == "__main__":
    d = {"A":"T","T":"A","G":"C","C":"G"}
    print(d[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):
dic={}
dic['A'] = 'T'
dic['C'] = 'G'
dic['G'] = 'C'
dic['T'] = 'A'
b = input()
print(dic[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':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')
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()
if b == "A":
    print("T")
elif b == "T":
    print("A")
elif b == "C":
    print("G")
elif b == "G":
    print("C")

Solution (Python):
b = input()
s = "ACGT"
t = "TGCA"
print(t[s.find(b)])

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

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

Solution (Python):

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

Solution (Python):


b = input()
text = 'ATCGTAGC'
print(text[text.find(b)+4])

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=str(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()
l="AGCTTCGA"
print(l[l.find(b)+4])

Solution (Python):
b = input()
AT = ['A','T']
CG = ['C','G']

if b in AT:
  print(list(set(AT)-set(b))[0])
else:
  print(list(set(CG)-set(b))[0])

Solution (Python):
b=input()
a=["A","T"]
c=["C","G"]
if b in a:
  a.remove(b)
  r = a 
else:
  c.remove(b)
  r = c
print("".join(r))

Solution (Python):
s = input()

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

Solution (Python):
a = input()

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

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

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

main()

Solution (Python):
s=input()

if s=='A': 
	res='T'
else:
	if s=='T':
		res='A'
	else:
		if s=='G':
			res='C'
		else:
			res='G'

print(res)

Solution (Python):
b = input()

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

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

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

Solution (Python):
enki_list_1 = ["A","T"]
enki_list_2 = ["C","G"]

b = input()
if (b=="A") or (b=="T"):
  enki_list_1.remove(b)
  print(enki_list_1[0])
else:
  enki_list_2.remove(b)
  print(enki_list_2[0])

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):
s= input()
ans=""
for j in s:
  if j =="A":
    ans += "T"
  elif j =="T":
    ans += "A"
  elif j == "C":
    ans += "G"
  else:
    ans += "C"
print(ans)

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

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

Solution (Python):
n=input();m="ATACGC";print(m[m.index(n)+1])

Solution (Python):
b = input()

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

Solution (Python):
b = input()
tmp = ['A','T','A','C','G','C']
for i in range(6):
  if b == tmp[i]:
    print(tmp[i+1])
    break

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

Solution (Python):

b=input()
if "AT".find(b) != -1:
    print("A" if b == 'T' else "T")
if "CG".find(b) != -1:
    print("C" if b == 'G' else "G")

Solution (Python):
s1 = 'ACGT'
s2 = 'TGCA'
s = str(input())
for i in range(len(s1)):
  if s == s1[i]:
    print(s2[i])

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()
print({"A":"T","T":"A","G":"C","C":"G"}[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):
"""


 = sys.stdin.readline().rstrip()
 = list(sys.stdin.readline().rstrip())


 = int(sys.stdin.readline())
 = map(int, sys.stdin.readline().split())
 = list(map(int, sys.stdin.readline().split()))
 = [list(map(int,list(sys.stdin.readline().split()))) for i in range(h)]  


a = 100
b = 0.987654321
print("{0:06d}-{1:6f}".format(a,b))
000100-0.987654


char_list = list("abcd") 
"""

import math
import sys
import itertools
import queue
from fractions import gcd

def lcm(a, b):
    return a * b // gcd(a, b)

mod = 1000000007

if __name__ == "__main__":
    b = sys.stdin.readline().rstrip()
    if b == "A":
        print("T")
    elif b == "C":
        print("G")
    elif b == "G":
        print("C")
    elif b == "T":
        print("A")

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

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