#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll INF = mod * mod;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)

ll gcd(ll a, ll b)
{
    if (a==0) return b; 
    else if (b==0) return a; 
    
    else if (a>b) return gcd(b, a%b);
    else return gcd(a, b%a); 
}

int main()
{
    ll T, A, B; cin >> T >> A >> B;

    ll C = A * B / __gcd(A, B);
    ll ans = (ll)(T-1)/A + (ll)(T-1)/B - (ll)(T-1)/C + 1;
    cout << ans << endl; 
}