#include <bits/stdc++.h>   using namespace std;   int gcd(int a, int b) { return a % b == 0 ? b : gcd(b, a % b); }   const int MAXN = 3e5 + 10;   const int INF = 0x3f3f3f3f;   const int MOD = 1e7 + 9;   int a[MAXN];   int main() {     int n;     scanf( %d , &n);     for (int i = (1); i < (n + 1); ++i) {       scanf( %d , &a[i]);     }     int ans1 = 0;     int t1 = 1;     for (int i = (n); i > (0); --i) {       if (a[t1] != a[i]) {         ans1 = i - t1;         break;       } else {         t1++;         i++;       }     }     int ans2 = 0;     int t2 = n;     for (int i = (1); i < (n + 1); ++i) {       if (a[t2] != a[i]) {         ans2 = t2 - i;         break;       } else {         t2--;         i--;       }     }     printf( %d n , max(ans1, ans2));     return 0;   }   