func_code_string: #include <bits/stdc++.h>   using namespace std;   long long power(long long x, long long y) {     long long res = 1;     x = x % 1000000007;     while (y > 0) {       if (y & 1) res = (res * x) % 1000000007;       y = y >> 1;       x = (x * x) % 1000000007;     }     return res % 1000000007;   }   long long inv(long long n) { return power(n, 1000000007 - 2) % 1000000007; }   long long isprime(long long n) {     if (n < 2) return 0;     long long i;     for (i = 2; i * i <= n; i++)       if (n % i == 0) return 0;     return 1;   }   void solve() {     long long ans = 1e18;     string s;     long long n;     cin >> n >> s;     for (char ch =  a ; ch <=  z ; ch++) {       long long i = 0, j = n - 1;       long long moves = 0;       long long ok = 1;       while (i < j) {         if (s[i] == s[j]) {           i++, j--;         } else if (s[i] == ch) {           i++;           moves++;         } else if (s[j] == ch) {           j--;           moves++;         } else {           ok = 0;           break;         }       }       if (ok) {         ans = min(ans, moves);       }     }     if (ans > n) ans = -1;     cout << ans <<   n ;   }   int32_t main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long t = 1;     long long tc = 0;     cin >> t;     while (t--) {       tc++;       solve();     }   }   