unsigned long long int gcd(int x, int y){
  while(x != 0){
    int z = x;
    x = y%x;
    y = z;
  }
  return y;
} 

unsigned long long int lcm(int x, int y){
    int p = gcd(x, y);
    int s = x*y/p;
    return s;
}

unsigned long long int main(){
    unsigned long long int t, a, b, l, c, d, e, f;
    scanf("%llu%llu%llu", &t, &a, &b);
    l = lcm(a, b);
    if (t%a == 0){
     d = t/a;   
    }
    else {
     d = 1+t/a;
    }
    if (t%b == 0){
     e = t/b;   
    }
    else {
     e = 1+t/b;
    }    
    if (t%l == 0){
     f = t/l;   
    }
    else {
     f = 1+t/l;
    }    
    c = d+e-f;
    printf("%llu\n", c);
    return 0;
    
    
    
}