#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 10000000000000000

long long gcd(long long a, long long b){
	if (b == 0) return a;
	return gcd(b, a % b);
}

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

	long long a = T/A;
	long long b = T/B;
	a++;b++;
	
	long long g = gcd(A,B);
	
	long long c = T/(A/g);
	c /= B;
	c++;
	cout<<a+b-c<<endl;
	
	return 0;
}