import math as m

def lcm(x, y):
    return (x * y) // m.gcd(x, y)

T, A, B = map(int, input().split())
T = m.floor(T)

#How many times bus A departs ?
x = T/A
y = T/B

#How many times both buses depart simultaneously?
xy = T/lcm(A, B)

print(int(x + y - xy))