import sequtils,strutils,math
var
    T, A, B : int64
(T, A, B) = stdin.readline.split.map(parseInt)
var
    a = (T - 1) div A + 1
    b = (T - 1) div B + 1
    g = gcd(A, B)
if T.float64 < A.float64 * B.float64 / g.float64:
    echo a + b - 1
else:
    var l = (T - 1) div (A * (B div g)) + 1
    echo a + b - l