#include <stdio.h>
#define MAXN 50

int x[MAXN];
int y[MAXN];

int main(void) {
    int n;

    scanf(" %d", &n);
    for (int i = 0; i < n; i++) {
        scanf(" %d %d", &x[i], &y[i]);
    }

    int ok = 1;
    for (int i = 0; i < n; i++) {
        if (x[0] != x[i]) {
            ok = 0;
        }
    }
    if (ok == 0) {
        ok = 1;
        for (int i = 0; i < n; i++) {
            if (y[0] != y[i]) {
                ok = 0;
            }
        }
    }
    if (ok) {
        printf("YES\n");
    } else {
        printf("NO\n");
    }
    return 0;
}