#include <bits/stdc++.h>
using namespace std;

long long int gcd(long long int,long long int);

int main(){
	long long int T,A,B,C,ans=0;
	cin >> T >> A >> B;
	ans+=(T+A-1)/A;
	ans+=(T+B-1)/B;
	C=(A*B/(gcd(A,B)));
	ans-=(T+C-1)/C;
	cout << ans << endl;
	return 0;
}
long long int gcd(long long int a,long long int b){
	if(b==0){
		return a;
	}
	return gcd(b,a%b);
}