We have a 3×3 square grid, where each square contains a lowercase English letters.
The letter in the square at the i-th row from the top and j-th column from the left is c_{ij}.
Print the string of length 3 that can be obtained by concatenating the letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

-----Constraints-----
 - Input consists of lowercase English letters.

-----Input-----
Input is given from Standard Input in the following format:
c_{11}c_{12}c_{13}
c_{21}c_{22}c_{23}
c_{31}c_{32}c_{33}

-----Output-----
Print the string of length 3 that can be obtained by concatenating the letters on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

-----Sample Input-----
ant
obe
rec

-----Sample Output-----
abc

The letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid are a, b and c from top-right to bottom-left. Concatenate these letters and print abc.

Difficulty: introductory

Starter code:

Solutions:
cij = [list(input()) for _ in range(3)]

print(cij[0][0] + cij[1][1] + cij[2][2])

def resolve():
    matrix = []
    for i in range(3):
        line = input()
        matrix.append(line)
    ans = ""
    for i in range(3):
        ans += matrix[i][i]
    print(ans)
resolve()

print("".join(input()[i]for i in(0,1,2)))

c1=str(input())
c2=str(input())
c3=str(input())
print(c1[0]+c2[1]+c3[2])

c = [input() for _ in range(3)]
print(c[0][0]+c[1][1]+c[2][2])

S1,S2,S3 = [input() for _ in range(3)]
print(S1[0]+S2[1]+S3[2])

print(*[input()[i] for i in range(3)],sep='')

a = input()[0]
s = input()[1]
d = input()[2]
print(a+s+d)

ans = ''

for i in range(3):
   ans += input()[i]

print(ans)

ans = []
for i in range(3):
  c = input()
  ans.append(c[i])
print("".join(ans))

c=[input() for i in range(3)]
print(*[c[i][i] for i in range(3)],sep="")

S1 = input()
S2 = input()
S3 = input()
print((S1[0] + S2[1] + S3[2]))


s = [list(input()) for _ in range(3)]
print("".join([s[i][i] for i in range(3)]))

c=[input() for _ in range(3)]
print((c[0][0]+c[1][1]+c[2][2]))


c=[input() for _ in range(3)]
print(c[0][0]+c[1][1]+c[2][2])

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

x = [input() for i in range(3)]
print(x[0][0]+x[1][1]+x[2][2])

C = [input() for _ in range(3)]
print(C[0][0] + C[1][1] + C[2][2])

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

res = ""
for i in range(3):
    line = input()
    res += line[i]

print(res)


print(input()[0] + input()[1] + input()[2])

x=[input() for _ in range(3)]
for i in range(3):
    print(x[i][i],end="")

A = []
for i in range(3):
    A.append(input())
print(A[0][0]+A[1][1]+A[2][2])

ans = ""
for i in range(3):
    ans += input()[i]
else:
    print(ans)

#k = int(input())
#s = input()
#a, b = map(int, input().split())
#s, t = map(str, input().split())
#l = list(map(int, input().split()))
#l = [list(map(int,input().split())) for i in range(n)]
#a = [list(input()) for _ in range(n)]
#a = [int(input()) for _ in range(n)]

c1 = input()
c2 = input()
c3 = input()

print((c1[0]+c2[1]+c3[2]))







c=[list(input()) for i in range(3)]
print(c[0][0]+c[1][1]+c[2][2])

a = input()
b = input()
c = input()
print(a[0] + b[1] + c[2])

a = input()
b = input()
c = input() 
print((a[0] + b[1] + c[2]))


a = map(str, input().split())
line_a = ''.join(a)

b = map(str, input().split())
line_b = ''.join(b)

c = map(str, input().split())
line_c = ''.join(c)

print('{}{}{}'.format(line_a[0], line_b[1], line_c[2]))

c = [input() for _ in range(3)]
for i in range(3):
    print(c[i][i], end="")

#!/usr/bin/env python3


c1 = str(input())
c2 = str(input())
c3 = str(input())


print((c1[0]+c2[1]+c3[2]))


a,b,c=input(),input(),input()
print(a[0]+b[1]+c[2])

c = []

for i in range(3):
    tmp = input()
    c.append(tmp)

ans = ""
for i in range(3):
    ans += c[i][i]

print(ans)

a = list(input())
b = list(input())
c = list(input())

print(a[0] + b[1] + c[2])

str1 = input()
str2 = input()
str3 = input()

print(str1[0]+str2[1]+str3[2])

a = input()
b = input()
c = input()
print(a[0] + b[1] + c[2])

c1 = list(input())
c2 = list(input())
c3 = list(input())

print(c1[0]+c2[1]+c3[2])

a = input()
b = input()
c = input()
print(a[0] + b[1] + c[2])

a = input()
b = input()
c = input()
print((a[0] + b[1] + c[2]))


a = input()
b = input()
c = input()
print(a[0]+b[1]+c[2])

print(''.join([input()[i] for i in range(3)]))

c = [list(input()) for i in range(3)]

print(c[0][0]+c[1][1]+c[2][2])

N_list = []

for i in range(3):
    N = input()
    N_i = N[0:3]
    N_list.append(N_i)
    i += 1
    
print(N_list[0][0] + N_list[1][1] + N_list[2][2])

print(input()[0]+input()[1]+input()[2])

cs=[input() for i in range(3)]
print(cs[0][0]+cs[1][1]+cs[2][2])

l = []
for i in range(3):
  l.append(input())
print(l[0][0]+l[1][1]+l[2][2])

c1 = str(input())
c2 = str(input())
c3 = input()
print(c1[0]+c2[1]+c3[2])

print(''.join([input()[i] for i in range(3)]))

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])


c1=list(map(str,input()))
c2=list(map(str,input()))
c3=list(map(str,input()))
print(c1[0]+c2[1]+c3[2])

s = ""
for i in range(3):
  s += input()
print(s[0] + s[4] + s[8])

ls = []
for i in range(3):
  ls.append(input())
ans = ''
for i in range(3):
  ans += ls[i][i]
print(ans)

def main():
    cat = "".join
    data = cat(input() for _ in range(3))
    print((cat([data[0], data[4], data[8]])))


main()


a = input()
b = input()
c = input()

print((a[0] + b[1] + c[2]))


#
# abc090 a
#
import sys
from io import StringIO
import unittest


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)

    def test_入力例_1(self):
        input = """ant
obe
rec"""
        output = """abc"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """edu
cat
ion"""
        output = """ean"""
        self.assertIO(input, output)


def resolve():
    C1 = input()
    C2 = input()
    C3 = input()

    print((C1[0]+C2[1]+C3[2]))


def __starting_point():
    # unittest.main()
    resolve()

__starting_point()

n = input()
n1 = input()
n2 = input()

print(n[0],n1[1],n2[2], flush=True,sep='')



c = [str(input()) for i in range(3)]
w = c[0][0]+c[1][1]+c[2][2]
print(w)

moji1 = str(input())
moji2 = str(input())
moji3 = str(input())

print(moji1[0]+moji2[1]+moji3[2])

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

c1 = input()
c2 = input()
c3 = input()

print(c1[0]+c2[1]+c3[2])

for i in range(3):
    s = input()
    print(s[i], end='')

A = list(input())
B = list(input())
C = list(input())

print(f"{A[0]}{B[1]}{C[2]}")

print(input()[0]+input()[1]+input()[2])

a = str(input())
b = str(input())
c = str(input())
print(a[0]+b[1]+c[2])

c1=input()
c2=input()
c3=input()
print(c1[0],end="")
print(c2[1],end="")
print(c3[2])

a = input()
b = input()
c = input()
print(a[0]+b[1]+c[2])

l=input()[0]
l+=input()[1]
l+=input()[2]
print(l)

a = input()
b = input()
c = input()

print(a[0]+b[1]+c[2])

import sys
s = sys.stdin.read().split()
print(s[0][0] + s[1][1] + s[2][2])

a = input()
b = input()
c = input()
print(a[0]+b[1]+c[2])

[print(input()[i],end='') for i in range(3)]

print(input()[0]+input()[1]+input()[2])

s = input()
t = input()
u = input()
print(s[0]+t[1]+u[2])

c_lst = [str(input()) for _ in range(3)]
ans = ''
for i in range(3):
    ans += c_lst[i][i]
print(ans)

c = []
for i in range(3):
  c += [input()]
  
print(c[0][0] + c[1][1]  + c[2][2])

cs=[""]*3
for i in range(3):
    cs[i]=input()
print(cs[0][0]+cs[1][1]+cs[2][2])

c1 = input()
c2 = input()
c3 = input()

print(c1[0] + c2[1] + c3[2])

a = [input() for _ in range(3)]
print(a[0][0] + a[1][1] + a[2][2])

import sys
C = sys.stdin.readlines()
print(C[0][0]+C[1][1]+C[2][2])

c1 = input()
c2 = input()
c3 = input()
print("".join(c1[0]+c2[1]+c3[2]))

c1 = str(input())
c2 = str(input())
c3 = str(input())

ans = c1[0] + c2[1] + c3[2]
print(ans)

ans = ''
ans += input()[0]
ans += input()[1]
ans += input()[2]
print(ans)


i1=input()
i2=input()
i3=input()
print(str(i1[0])+str(i2[1])+str(i3[2]))

c1 = list(input())
c2 = list(input())
c3 = list(input())

print(c1[0] + c2[1] + c3[2])

a = input()[0]
b = input()[1]
c = input()[2]
print(a+b+c)

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

S = [input() for i in range(3)]
print(S[0][0]+S[1][1]+S[2][2])

a = [list(input()) for i in range(3)]

print(a[0][0]+a[1][1]+a[2][2])

l1 = input ()
l2 = input ()
l3 = input ()
print (l1[0]+l2[1]+l3[2])

c1=str(input())
c2=str(input())
c3=str(input())

print(c1[0]+c2[1]+c3[2])

n = list(input())
n1 = list(input())
n2 = list(input())

print(n[0]+n1[1]+n2[2])

c1 = input()[0]
c2 = input()[1]
c3 = input()[2]
print((c1+c2+c3))


a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])


def main():
    c = [input() for _ in range(3)]
    print((c[0][0] + c[1][1] + c[2][2]))


def __starting_point():
    main()

__starting_point()

c1 = input()
c2 = input()
c3 = input()
print(c1[0]+c2[1]+c3[2])

cs=[]
for i in range(3):
    cs.append(input())
print(cs[0][0]+cs[1][1]+cs[2][2])

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

S = [input() for _ in range(3)]
print(S[0][0]+S[1][1]+S[2][2])

a=input()
b=input()
c=input()
print(a[0]+b[1]+c[2])

a = input()
b = input()
c = input()
print(a[0]+b[1]+c[2])