import math
s1 = input()
s2 = input()
diff = 0
for i in range(len(s1)):
if s1[i] != s2[i]: diff+=1
if diff%2==1:
print("impossible")
else:
i = j = 0
while i<len(s1):
print(s1[i], end = '')
if s1[i] != s2[i]: j+=1
if j==diff//2: break
i+=1
print(s2[i+1:])
#include <iostream>
using namespace std;
string compare(string a, string b) {
if(a > b) {
string t = a;
a = b;
b = t;
}
int c = 0, d = a.length(), i, j;
for(i = 0; i < d; i++)
if (a[i] != b[i]) c++;
if (c % 2 > 0) return "impossible";
for(j = c, i = 0; i < d && j > c / 2; i++)
if (a[i] != b[i]) {
b[i] = a[i];
j--;
}
return b;
}
int main() {
string a, b;
cin >> a >> b;
cout << compare(a, b);
}
461. Hamming Distance | 1748. Sum of Unique Elements |
897. Increasing Order Search Tree | 905. Sort Array By Parity |
1351. Count Negative Numbers in a Sorted Matrix | 617. Merge Two Binary Trees |
1450. Number of Students Doing Homework at a Given Time | 700. Search in a Binary Search Tree |
590. N-ary Tree Postorder Traversal | 589. N-ary Tree Preorder Traversal |
1299. Replace Elements with Greatest Element on Right Side | 1768. Merge Strings Alternately |
561. Array Partition I | 1374. Generate a String With Characters That Have Odd Counts |
1822. Sign of the Product of an Array | 1464. Maximum Product of Two Elements in an Array |
1323. Maximum 69 Number | 832. Flipping an Image |
1295. Find Numbers with Even Number of Digits | 1704. Determine if String Halves Are Alike |
1732. Find the Highest Altitude | 709. To Lower Case |
1688. Count of Matches in Tournament | 1684. Count the Number of Consistent Strings |
1588. Sum of All Odd Length Subarrays | 1662. Check If Two String Arrays are Equivalent |
1832. Check if the Sentence Is Pangram | 1678. Goal Parser Interpretation |
1389. Create Target Array in the Given Order | 1313. Decompress Run-Length Encoded List |