/********************************************
*                                           *
*    Solved By : Bir Bahadur Khatri(B'ru)   *
*      Be Positive,be Happy.                *
*                                           *
*********************************************/

#define ff first
#define D double
#define sz size()
#define ss second
#define PB push_back
#define MP make_pair
#define SQR(n) (n*n)
#define CHR getchar()
#define NL printf("\n")
#include<bits/stdc++.h>
#define ULL unsigned LL
#define PI 2.0*acos(0.0)
#define LL long long int
#define Max(a,b) ((a>b)?a:b)
#define Min(a,b) ((a<b)?a:b)
#define S1(a)  scanf("%d",&a)
#define SL1(a) scanf("%lld",&a)
#define all(a) a.begin(),a.end()
#define _Max(a,b,c) Max(a,Max(b,c))
#define _Min(a,b,c) Min(a,Min(b,c))
#define S2(a,b) scanf("%d%d",&a,&b)
#define F(i,a,b) for(int i=a;i<b; i++)
#define SL2(a,b) scanf("%lld%lld",&a,&b)
#define R(i,a,b) for(int i=a-1;i>=b; i--)
#define BitCnt(a) __builtin_popcountll(a)
#define MEM(a,val) memset(a,val,sizeof(a))
#define S3(a,b,c)  scanf("%d%d%d",&a,&b,&c)
#define SL3(a,b,c) scanf("%lld%lld%lld",&a,&b,&c)
#define cp printf("***** here here here here *****\n");
#define trace1(x)                cerr << #x << ": " << x << endl;
#define InpOut freopen("A.in","r",stdin),freopen("A1.out","w",stdout)
#define trace2(x, y)             cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z)          cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
#define trace4(a, b, c, d)       cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << endl;

using namespace std;
template<typename T>inline T POW(T B,T P){ if(P==0) return 1; if(P&1) return B*POW(B,P-1);  else return SQR(POW(B,P/2));}
template<typename T>inline T Gcd(T a,T b){if(a<0)return Gcd(-a,b);if(b<0)return Gcd(a,-b);return (b==0)?a:Gcd(b,a%b);}
template<typename T>inline T Lcm(T a,T b) {if(a<0)return Lcm(-a,b);if(b<0)return Lcm(a,-b);return a*(b/Gcd(a,b));}
long long Bigmod(long long base, long long power, long long MOD){long long ret=1;while(power){if(power & 1)ret=(ret*base)%MOD;base=(base*base)%MOD;power>>=1;}return ret;}
bool isVowel(char ch){ ch=toupper(ch); if(ch=='A'||ch=='U'||ch=='I'||ch=='O'||ch=='E') return true; return false;}
long long ModInverse(long long number, long long MOD){return Bigmod(number, MOD-2, MOD);}
bool isConst(char ch){if (isalpha(ch) && !isVowel(ch)) return true; return false;}
int toInt(string s)  { int sm; stringstream ss(s); ss>>sm; return sm; }

///**********************************************************//

#define MD1 1000000007ULL
#define MD2 1000000009ULL
#define MD3 1000000021ULL
#define BS1 10000019ULL
#define BS2 10000079ULL
#define BS3 10000103ULL
#define PUL pair<ULL,ULL>
#define PII pair<int,int>

///         0123456789
#define MX  500007
#define MOD 1000000007
#define INF 2000000000
#define EPS 1e-9
/// ==========================================////

PII a[10002];

int main()
{
    int n;
    cin>>n;

    F(i,1,n+1) {
        cin>>a[i].ff>>a[i].ss;
    }
    sort(a+1,a+n+1);

    if(a[1].ff==a[n].ff) {
     printf("YES\n");
    }
    else {

        F(i,1,n+1) swap(a[i].ff,a[i].ss);
        sort(a+1,a+n+1);

        if(a[1].ff==a[n].ff) {
         printf("YES\n");
        }
        else {
            printf("NO\n");
        }
    }


    return 0;
}