import sys

def main() -> None:
    # 高速入力
    it = iter(sys.stdin.read().strip().split())
    n = int(next(it))

    seen = set()       # (Ai, Bi) を格納
    for _ in range(n):
        a = int(next(it))
        b = int(next(it))
        if (a, b) in seen:   # すでに同じ月日が出てきた
            print("Yes")
            return
        seen.add((a, b))

    # 最後まで重複なし
    print("No")

if __name__ == "__main__":
    main()