def pair_front_and_back(s: str):
temp=''
for i in range(len(s)//2):
temp+=s[i]+s[len(s)-i-1]
if len(s)%2!=0:
temp+=s[len(s)//2]
return temp
print(pair_front_and_back('dinosaur'))
print(pair_front_and_back('metal'))
ZGVmIHBhaXJfZnJvbnRfYW5kX2JhY2soczogc3RyKToKCXRlbXA9JycKCWZvciBpIGluIHJhbmdlKGxlbihzKS8vMik6CgkJdGVtcCs9c1tpXStzW2xlbihzKS1pLTFdCglpZiBsZW4ocyklMiE9MDoKCQl0ZW1wKz1zW2xlbihzKS8vMl0KCXJldHVybiB0ZW1wCgkKcHJpbnQocGFpcl9mcm9udF9hbmRfYmFjaygnZGlub3NhdXInKSkKCnByaW50KHBhaXJfZnJvbnRfYW5kX2JhY2soJ21ldGFsJykp