#include <bits/stdc++.h>
using namespace std;
#define int long long
#define FOR(i, s, n) for (int i = (s); i < (int)(n); i++)
#define RFOR(i, s, n) for (int i = (n) - 1; i >= (int)(s); i--)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define ALL(a) a.begin(), a.end()
constexpr long long INF = 1e18;
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a=b;return true;}return false;}

int gcd(int x,int y)
{
	if(x==0) return y;
	return gcd(y%x,x);
}
unsigned int lcm(int x, int y)
{
	return (x / gcd(x, y) * y);
}

signed main(){
	int T,A,B;
	cin >> T >> A >> B;
	T--;
	unsigned int ans = T / A + T / B - T / lcm(A,B);
	cout << 1 + ans << endl;
}