T, A, B = map(int,input().split())
La = []
C = 0
for i in range(1, B+1):
    a = A*i
    La.append(a)
for i in range(1, A+1):
    b = B*i
    if b in La:
        C = b
        break
ca = 1 + ((T-1) // A)
cb = 1 + ((T-1) // B)
sub = 1 + ((T-1) // C)
cnt = ca + cb - sub
print(cnt)