# Principled Programming / Tim Teitelbaum / Chapter 5.
def e5_1_1() -> None:
    """ Print grades."""
    grade: int = int(input())    # Next grade to be processed, or -1.
    while grade != -1:
        print(grade)
        grade = int(input())

def e5_1_2() -> None:
    """Count grades."""
    grade: int = int(input())    # Next grade to be processed, or -1.
    count: int = 0  # The number of grades processed so far.
    while grade != -1:
        count += 1
        grade = int(input())
    print(count)

def e5_1_3() -> None:
    """Average grade."""
    grade: int = int(input())    # Next grade to be processed, or -1.
    count: int = 0  # The number of grades processed so far.
    sum: int = 0  # The sum of the grades processed so far.
    while grade != -1:
        count += 1; sum = sum + grade
        grade = int(input())
    if count == 0: print("no grades")
    else: print(sum / count)

def e5_1_4() -> None:
    """Highest grade."""
    grade: int = int(input())    # Next grade to be processed, or -1.
    highest: int = -1  # The highest grade processed
    while grade != -1:
        if grade > highest: highest = grade;
        grade = int(input())
    if highest == -1: print("no grades")
    else: print(highest)

def e5_1_5() -> None:
    """Distribution of grades."""
    grade: int = int(input())    # Next grade to be processed, or -1.
    freq  = [0] * 101  # For 0≤k≤100, freq[k] is number of grades of k processed so far.
    while grade != -1:
        freq[grade] += 1
        grade = int(input())
    print("grade frequency")
    for g in range(101): print( g, freq[g])

def e5_2_1() -> None:
    """
    Given 0 or more nonnegative inputs followed by a stopping signal of -1,
    output the equivalent run-encoded sequence followed by -1 -1.
    """

    v: int = int(input())   # Next integer to be processed, or -1.
    r: int = v  # The run prefix is of r values.
    n: int = 0  # The processed prefix has length n.
    while v != -1:
        if v==r: n += 1
        else:
            print( r, n )
            r = v; n = 1
        v = int(input())
    if n != 0: print(r, n);
    print("-1 -1")

def e5_2_2() -> None:
    """
    Given zero or more pairs of integers ⟨r,n⟩, each pair representing a
    run encoding of n r’s, followed by the pair ⟨-1,-1⟩, output the
    decoding, followed by -1.
    """

    r, n = input().split(); r = int(r); n = int(n)
    while r != -1:
        for k in range (0,n):  print( r )
        r, n = input().split(); r = int(r); n = int(n)
    print(-1)

# Uncomment line to run.
#e5_1_1()
#e5_1_2()
#e5_1_3()
#e5_1_4()
#e5_1_5()
#e5_2_1()
#e5_2_2()