#include<cstdio>
#include<cstring>
const int maxn=1010;
char S[maxn];
int dp[maxn][maxn];
int main(){
gets(S);
int len=strlen(S),ans=1;
memset(dp,0,sizeof(dp));
for(int i=0;i<len;i++){
dp[i][i]=1;
if(i<len-1){
if(S[i]==S[i+1]){
dp[i][i+1]=1;
ans=2;
}
}
}
for(int L=3;L<=len;L++){
for(int i=0;i+L-1<len;i++){
int j=i+L-1;
if(S[i]==S[j]&&dp[i+1][j+1]==1){
dp[i][j]=1;
ans=L;
}
}
}
printf("%d\n",ans);
return 0;
}