1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Vi = vector<int>;
using Pii = pair<int, int>;
using Pli = pair<ll, int>;
#define pb push_back
#define rep(i,b,e) for(int i=(b); i<(e); i++)
#define each(a,x) for(auto& a : (x))
#define all(x) (x).begin(),(x).end()
#define sz(x) int((x).size())
#define endl "\n"
#define x first
#define y second
const int inf = 1e9 + 10;
const ll mod = 1e9 + 7;



void solve() {
	int n, k;
	cin >> n >> k;
	int res = 3000;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= i; j++) {
			int x;
			cin >> x;
			if (j * (i-j + 1) <= k) res = min(res, x);
		}
	}
	cout << res << endl;
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(18);
	solve();
	return 0;
}