#include <iostream>
#include <vector>
#include<iomanip>
#include<functional>
#include<algorithm>
#include<deque>
#include<math.h>
#include<set>
#include<cstdio>
#include<string>
#include<queue>
#include<complex>
#include<numeric>
#include<stack>
#include<unordered_map>
#include<map>
#include <cassert>
#include<random>
using namespace std;
#define rep(i,n) for(int i = 0;i<n;i++)
#define req(i,n) for(ll i = 1;i<=n;i++)
#define rrep(i,n) for(int i = n-1;i>=0;i--)
#define ALL(a) a.begin(),a.end()
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef long long ll;
typedef long double ld;
const ll mod = 1e9 + 7;
ll gcd(ll a, ll b) {
    return b ? gcd(b, a % b) : a;
}
int main() {
    ll a, b, t; cin >> t >> a >> b; t--;
    cout << t / a + t / b - t / (a / gcd(a, b)) / b+1 << endl;
}