N=int(input())
w=input()
l=list()
ll=0
lw=0
for i in range(0,N):
for j in range(i,N+1):
s=w[i:j]
#print(s)
if (s==s[len(s)::-1] and len(s)>ll):
#print(s[len(s)::-1])
ll=len(s)
lw=s[len(s)::-1]
print(ll)
print(lw)
Tj1pbnQoaW5wdXQoKSkKdz1pbnB1dCgpCmw9bGlzdCgpCmxsPTAKbHc9MApmb3IgaSBpbiByYW5nZSgwLE4pOgogICAgZm9yIGogaW4gcmFuZ2UoaSxOKzEpOgogICAgICAgIHM9d1tpOmpdCiAgICAgICAgI3ByaW50KHMpCiAgICAgICAgaWYgKHM9PXNbbGVuKHMpOjotMV0gYW5kIGxlbihzKT5sbCk6CiAgICAgICAgICAgICNwcmludChzW2xlbihzKTo6LTFdKQogICAgICAgICAgICBsbD1sZW4ocykKICAgICAgICAgICAgbHc9c1tsZW4ocyk6Oi0xXQpwcmludChsbCkKcHJpbnQobHcp