#include <bits/stdc++.h>
using namespace std;
int t[1005], n;
int spelnia(double d) {
  double bak = d;
  long long j = 0;
  for (int i = 0;;) {
    if (bak < 100) {
      bak += d;
      if (j < t[i]) {
        return -1;
      }
      if (j > t[i]) {
        return 1;
      }
      if (++i == n) {
        return 0;
      }
    }
    long long ile = (long long)floor(bak / 100.);
    j += ile;
    bak -= (ile * 100.);
  }
}
int next(double d) {
  double bak = d;
  for (int i = 0, j = 0;; ++j, bak -= 100) {
    if (bak < 100) {
      if (i++ == n) {
        return j;
      }
      bak += d;
    }
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d", t + i);
  }
  double a = 100, b = 1e11;
  for (; fabs(a - b) > 1e-6;) {
    double d = (a + b) / 2;
    if (spelnia(d) < 0) {
      a = d;
    } else {
      b = d;
    }
  }
  double dol = b;
  a = 100, b = 1e11;
  for (; fabs(a - b) > 1e-6;) {
    double d = (a + b) / 2;
    if (spelnia(d) <= 0) {
      a = d;
    } else {
      b = d;
    }
  }
  double gora = a;
  int n1 = next(dol), n2 = next(gora);
  if (n1 == n2) {
    printf("unique\n%d\n", n1);
  } else {
    puts("not unique");
  }
}
