#include <stdio.h>
#include <stdbool.h>

int main(void) {
    int N;
    scanf("%d", &N);
    static bool seen[1001][1001] = { false };

    for (int i = 0; i < N; i++) {
        int month, day;
        scanf("%d %d", &month, &day);

        if (seen[month][day]) {
            puts("Yes");
            return 0;
        }
        seen[month][day] = true;
    }

    puts("No");
    return 0;
}