def haha(arr,n):
arr.sort()
i=0
while(i<n-2):
a=arr[i]
b=arr[i+1]
c=arr[i+2]
if(a+b>c and a+c>b and b+c>a):
return "YES"
i+=1
return "NO"
n=int(input())
arr=list(map(int,input().split()))
x=haha(arr,n)
print(x)#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
bool solve()
{
int n;
cin >> n;
ll num[n];
for(auto &x: num)
cin >> x;
sort(num, num+n);
for(int i = 0; i < n-2; i++)
{
if(num[i]+num[i+1] > num[i+2] && num[i]+num[i+2] > num[i+1] && num[i+1]+num[i+2] > num[i])
return true;
}
return false;
}
int main()
{
//freopen("a.in", "r", stdin);
(solve())? cout << "YES" : cout << "NO";
} 1189A - Keanu Reeves | 678A - Johny Likes Numbers |
1699C - The Third Problem | 1697D - Guess The String |
754B - Ilya and tic-tac-toe game | 760A - Petr and a calendar |
1573A - Countdown | 166A - Rank List |
1631B - Fun with Even Subarrays | 727A - Transformation from A to B |
822B - Crossword solving | 1623A - Robot Cleaner |
884B - Japanese Crosswords Strike Back | 862B - Mahmoud and Ehab and the bipartiteness |
429A - Xor-tree | 1675C - Detective Task |
950A - Left-handers Right-handers and Ambidexters | 672B - Different is Good |
1C - Ancient Berland Circus | 721A - One-dimensional Japanese Crossword |
1715B - Beautiful Array | 60B - Serial Time |
453A - Little Pony and Expected Maximum | 1715A - Crossmarket |
1715C - Monoblock | 1512C - A-B Palindrome |
1679B - Stone Age Problem | 402A - Nuts |
792A - New Bus Route | 221A - Little Elephant and Function |