#include <vector>
#include <algorithm>
#include <queue>
#include <map>
#include <set>
#include <unordered_map>
#include <time.h>
#include <iomanip>
#include <deque>
#include <math.h>
#include <assert.h>
#include <stack>
#include <bitset>
#include <random>
#include <fstream>



using namespace std;
ifstream cin("inversmodular.in"); ofstream cout("inversmodular.out");

void euclid(long long a, long long b, long long& d, long long& x, long long& y) {
 if (b == 0) {
  d = a;
  x = 1; y = 0;


 }
 else {
  long long x0, y0;
  euclid(b, a % b, d, x0, y0);
  x = y0;
  y = x0 - (a / b) * y0;


 }
}

int main() {

 long long a, b, d, x, y;
 cin >> a >> b;
 euclid(a, b, d, x, y);
 x = (x%b + b) % b;
 cout << x;

 return 0;
}