#include <iostream>
using namespace std;
template <typename T>
T gcd(T a,T b){
  if(a%b==0)return b;
  else return gcd(b,a%b);
}
template <typename T>
T lcm(T a,T b){
  return a/gcd(a,b)*b;
}
int main(){
    int a,b;cin>>a>>b;
    cout << a/gcd(a,b)-1 << endl;
}