#include using namespace std; #define X first #define Y second #define INPUT freopen("101hack.inp","r",stdin) #define OUTPUT freopen("101hack.out","w",stdout) #define FOR(i,l,r) for(auto i=(l);i<=(r);i++) #define REP(i,l,r) for(auto i=(l);i<(r);i++) #define FORD(i,l,r) for(auto i=(l);i>=(r);i--) #define REPD(i,l,r) for(auto i=(l);i>(r);i--) #define ENDL printf("\n") #define debug 1 typedef long long ll; typedef pair ii; const int inf=1e9; const int MOD=1e9+7; const int N=1e5+10; int n,a[2][N]; void prepare(){ scanf("%d",&n); FOR(i,1,n) FOR(j,0,1) scanf("%d",a[j]+i); FOR(i,0,1) if (count(a[i]+1,a[i]+n+1,a[i][1])==n){ printf("YES"); return; } printf("NO"); } int main(){ // freopen("input.inp","r",stdin); prepare(); }