#include <stdio.h>
#include <string>
#include <cstring>
#include <stdlib.h>
#include <math.h>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <assert.h>
#pragma warning(disable:4996) 
 
typedef long long ll;
#define MIN(a, b) ((a)>(b)? (b): (a))
#define MAX(a, b) ((a)<(b)? (b): (a))
#define LINF 9223300000000000000
#define INF 2140000000
const long long MOD = 1000000007;
using namespace std;

ll gcd(ll a, ll b) {
    if(b == 0) return a;
    return gcd(b,a%b);
}
ll lcm(ll a, ll b) {
    ll g = gcd(a,b);
    return a / g * b;   // Be careful not to overflow
}

int main(int argc, char* argv[])
{
    ll t,a,b;
    scanf("%lld%lld%lld", &t, &a, &b);

    printf("%lld\n", (t-1+a)/a + (t-1+b)/b - ((t-1)/a/(b/gcd(a,b))+1));

    return 0;
}