def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    n = int(input[idx])
    idx += 1
    pairs = []
    for _ in range(n):
        a = int(input[idx])
        b = int(input[idx + 1])
        pairs.append((a, b))
        idx += 2

    used = [False] * (n + 1)
    res = [0] * n

    # Process in reverse order (i from n-1 downto 0)
    for i in range(n-1, -1, -1):
        a, b = pairs[i]
        if not used[a] and not used[b]:
            # Choose the one that appears first; arbitrary choice to prefer a
            res[i] = a
            used[a] = True
        elif not used[a]:
            res[i] = a
            used[a] = True
        elif not used[b]:
            res[i] = b
            used[b] = True
        else:
            # Both are used, choose any (here a)
            res[i] = a

    # Check if all are used
    all_used = all(used[1:n+1])
    if not all_used:
        print("No")
    else:
        print("Yes")
        for num in res:
            print(num)

if __name__ == "__main__":
    main()