#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     double lo = 0.0, hi = 10000000.0;     for (int i = 1; i <= n; i++) {       int sta;       cin >> sta;       lo = max(lo, (double)10.0 * sta / i);       hi = min(hi, (double)10.0 * (sta + 1) / i);     }     int nextlo = floor(lo * (n + 1) / 10.0);     int nexthi = ceil(hi * (n + 1) / 10.0);     if (nextlo + 1 >= nexthi) {       cout <<  unique  << endl << nextlo << endl;     } else {       cout <<  not unique  << endl;     }     return 0;   }   