void solve() {

string s;
cin>>s;

int n=sz(s);
int mx=0;
for (int i=0;i<n/2;i++){
    if (s[i]==s[n-1-i]){
        mx++;
    }
    else break;
}

string g=s.substr(mx,n-2*mx);
string g2="";
for (int i=sz(g)-1;i>=0;i--){
    g2+=g[i];
}
//cout<<g<<' '<<g2<<endl;
int m=sz(g);
int ans=m;
vector <vector <int> > v(26),v2(26);
for (int i=0;i<m;i++){
    v[g[i]-'a'].pb(i);
}
mx=0;
for (int i=m-1,j=0;i>j;i--,j++){
    if (g[i]!=g[j]){
        int a=g[i]-'a',b=g[j]-'a';
        int l=sz(v[b])-1;
        if (l==-1){
            mx=INT_MAX;
            break;
        }
        mx=max(mx,m-v[b][l]);
         int ind=sz(v[a])-1;
          int x=v[b][l];
          int y=v[a][ind];
        v[a][ind]=x;
          v[b][l]=y;
        swap(g[i],g[x]);

    }
    v[g[i]-'a'].pop_back();
}
//cout<<g<<endl;
ans=min(ans,mx);
mx=0;

for (int i=0;i<m;i++){
    v2[g2[i]-'a'].pb(i);
}
for (int i=m-1,j=0;i>j;i--,j++){
    if (g2[i]!=g2[j]){
        int a=g2[i]-'a',b=g2[j]-'a';
        int l=sz(v2[b])-1;
        if (l==-1){
            mx=INT_MAX;
            break;
        }
        mx=max(mx,m-v2[b][l]);
         int ind=sz(v2[a])-1;
          int x=v2[b][l];
          int y= v2[a][ind];
          v2[a][ind]=x;
          v2[b][l]=y;
        swap(g2[i],g2[x]);

    }
    v2[g2[i]-'a'].pop_back();
}
//cout<<g2<<endl;
ans=min(ans,mx);
cout<<ans<<endl;

}