import sys
import math

def main():
    input = sys.stdin.read().split()
    idx = 0
    P = int(input[idx]); idx +=1
    Q = int(input[idx]); idx +=1
    N = int(input[idx]); idx +=1
    points = []
    for _ in range(N):
        x = int(input[idx]); idx +=1
        y = int(input[idx]); idx +=1
        points.append((x, y))
    
    count = 0
    
    if P == 0 and Q == 0:
        for x, y in points:
            if x == 0 and y == 0:
                count +=1
        print(count)
        return
    
    # Compute d = gcd(P, Q)
    d = math.gcd(P, Q)
    
    # Compute g = gcd(P+Q, P-Q)
    a = P + Q
    b = P - Q
    g = math.gcd(abs(a), abs(b))
    
    for x, y in points:
        # Check if x and y are multiples of d
        if x % d != 0 or y % d != 0:
            continue
        
        # Check sum and difference
        s = x + y
        t = x - y
        
        if s % g != 0 or t % g != 0:
            continue
        
        count +=1
    
    print(count)

if __name__ == "__main__":
    main()