#include<bits/stdc++.h>
#define ll long long
#define fr(i,j,k) for(register int i=j;i<=k;++i)
#define rf(i,j,k) for(register int i=j;i>=k;--i)
#define foredge(i,j) for(register int i=head[j];i;i=e[i].nxt)
#define pb push_back
#define Times printf("Time:%.3lf\n",clock()/CLOCKS_PER_SEC)
#define pii pair<int,int>
#define mk make_pair
using namespace std;
inline int read(){
	int x=0;
	bool f=0;
	char c=getchar();
	while(!isdigit(c)) f|=(c=='-'),c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return f?-x:x;
}
inline void write(int x){
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inline void writeln(int x){write(x); puts("");}
inline void writepl(int x){write(x); putchar(' ');}
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int randfind(int l,int r){return rnd()%(r-l+1)+l;}
//inline void init(){
//	int t=read();
//	while(t--) work();
//}
const int Maxn=4e3+10;
bitset<Maxn> bt[Maxn];
int n;
int a[Maxn][Maxn];
inline void init(){
    n=read();
    fr(i,1,n) for(int j=i+1;j<=n;j+=2) a[i][j]=read();
}
inline bool check(int x){
    fr(i,1,n) bt[i].reset();
    fr(i,1,n) bt[i+1][i]=1;
    rf(l,n,1) for(int r=l+1;r<=n;r+=2){
        if(bt[l+1][r-1] && a[l][r]<=x) bt[l][r]=1;
        if(bt[l][r]) bt[l]|=bt[r];
    }return bt[1][n];
}
inline void work(){
    int l=1,r=(n/2)*(n/2),ans=0;
    while(l<=r){
        int mid;mid=(l+r)>>1;
        if(check(mid)) ans=mid,r=mid-1;
        else l=mid+1;
    }writeln(ans);
}
signed main(){
	// freopen("input.in","r",stdin);
	// freopen("output.out","w",stdout);
    init();work();
    // printf("\nTIME:%.3lf",(double)clock()/CLOCKS_PER_SEC);
	return 0;
}