Longest Common Middle Substring

Longest Common Middle Substring: The program must accept two string values S1 and S2 as the input. The program must print the longest common middle substring in the given two string values as the output. If there is no such substring, then the program must print -1 as the output.
Note: The lengths of S1 and S2 are always odd.

Boundary Condition(s):
3 <= Length of S1, S2 <= 99

Input Format:
The first line contains S1.
The second line contains S2.

Output Format:
The first line contains the longest common middle substring or -1.

Example Input/Output 1:
Input:
doglionlizard
absolutionlizagging

Output:
ionli

Explanation:
The longest common middle substring is highlighted below
S1 = doglionlizard
S2 = absolutionlizagging
So ionli is printed as the output.

Example Input/Output 2:
Input:
CELEBRATE
millets

Output:
-1

Example Input/Output 3:
Input:
numbersgame
meterSONG

Output:
r

a=input().strip()
b=input().strip()
c=""
s1Ind,s2Ind=len(a)//2,len(b)//2
for ctr in range(0,min(s1Ind,s2Ind)+1):
    x=a[s1Ind-ctr:s1Ind+ctr+1]
    y=b[s2Ind-ctr:s2Ind+ctr+1]
    if x==y:
        c=x
if c=="":
    print(-1)
else:
    print(c)

a=”CELEBRATE” b=”millets” c=”” s1Ind,s2Ind=len(a)//2,len(b)//2 for ctr in range(0,min(s1Ind,s2Ind)+1): x=a[s1Ind-ctr:s1Ind+ctr+1] y=b[s2Ind-ctr:s2Ind+ctr+1] if x==y: c=x if c==””: print(-1) else: print(c)