#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<numeric>
using namespace std;
using i32 = int_fast32_t;
using i64 = int_fast64_t;
#define rep(i, n) for (i32 i = 0; i < (i32)(n); i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
using P = pair<i64,i64>;

int main(){
ios::sync_with_stdio(false);
std::cin.tie(nullptr);
i64 t,a,b;
cin >> t >> a >> b;
i64 ans = 0;
i64 ma = t / a;
i64 mb = t / b;
if(t % ma) ma++;
if(t % mb) mb++;
i64 mab = t / lcm(a,b);
if(mab != 0 && t % mab != 0) mab++;
ans = (ma + mb - mab);
cout << ans << endl;
}