def gcd(a,b):
    if(b==0):
        return a
    return gcd(b,a%b)
def lcm(a,b):
    return a*b//gcd(a,b)

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

lc = lcm(A,B)
cnt =0
if(T%A ==0):
    cnt = cnt + T//A
else:
    cnt = cnt + T//A + 1
if(T%B ==0):
    cnt = cnt + T//B
else:
    cnt = cnt + T//B +1

if(T%lc == 0):
    cnt -= T//lc
else:
    cnt -= T//lc +1

print(cnt)