n=int(input())
a=list(map(int,input().split()))
s=sorted(list(set(a)))
if len(s)<=1:
print("NO")
else:
print(s[1])
#include <cstdio>
int main(){
int temp(0), currentMin(101), secondMin(101);
int n; scanf("%d", &n);
while(n--){
scanf("%d", &temp);
if(temp < currentMin){secondMin = currentMin; currentMin = temp;}
else if (currentMin < temp && temp < secondMin){secondMin = temp;}
}
if(secondMin == currentMin || secondMin == 101){puts("NO");}
else{printf("%d\n", secondMin);}
return 0;
}137C - History | 1443C - The Delivery Dilemma |
6C - Alice Bob and Chocolate | 1077C - Good Array |
285B - Find Marble | 6A - Triangle |
1729A - Two Elevators | 1729B - Decode String |
1729C - Jumping on Tiles | 1729E - Guess the Cycle Size |
553B - Kyoya and Permutation | 1729D - Friends and the Restaurant |
1606C - Banknotes | 580C - Kefa and Park |
342A - Xenia and Divisors | 1033A - King Escape |
39D - Cubical Planet | 1453A - Cancel the Trains |
645A - Amity Assessment | 1144A - Diverse Strings |
1553B - Reverse String | 1073A - Diverse Substring |
630N - Forecast | 312B - Archer |
34D - Road Map | 630I - Parking Lot |
160B - Unlucky Ticket | 371B - Fox Dividing Cheese |
584B - Kolya and Tanya | 137B - Permutation |