#include <bits/stdc++.h>
using namespace std;
#define REP(i,a) for(int i = 0; i < (a); i++)
#define ALL(a) (a).begin(),(a).end()
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1e9;
const int MOD = 1e9 + 7;

long long GCD(long long m,long long n){
    if(n == 0) return m;
    else return GCD(n,m % n);
}

long long LCM(long long m,long long n){
    long long g = GCD(m,n);
    return m / g * n;
}

signed main(){
    ll t,a,b;
    cin >> t >> a >> b;
    ll c = LCM(a, b);
    cout << (t + a - 1) / a + (t + b - 1) / b - (t + c - 1) / c << endl;
}