#pragma region
#pragma GCC target("avx2")
#pragma GCC optimize("03")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std; typedef long double ld; typedef long long ll;
typedef unsigned long long ull;
#define endl "\n"
#define FOR(i,a,b) for(int i=(a);i<=(b);i++)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define ALL(x) (x).begin(), (x).end()
constexpr int INF=1<<30; constexpr ll LINF=1LL<<60; constexpr ll mod=1e9+7; constexpr int NIL = -1;
template<class T>inline bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>inline bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
#pragma endregion
//-------------------

ll GCD(ll a, ll b) {
    return b==0? a : GCD(b, a%b);
}

int main(){
    cin.tie(0); ios::sync_with_stdio(false); //cout << fixed << setprecision(15);
    ll t,a,b; cin >> t >> a >> b;

    t--;
    ll gcd = GCD(a,b);

    cout << t/a + t/b - (t/a)*gcd/b + 1 << endl;
    return 0;
}