#include <cstdio>

using namespace std;

void euclid(long long a,long long b,long long &x,long long &y)
{
    if(!b)
    {
        x = 1;
        y = 0;
        return;
    }
    long long x1,y1;
    euclid(b,a%b,x1,y1);
    x = y1;
    y = x1 - y1*(a/b);
}

int main()
{
    freopen("inversmodular.in","r",stdin);
    freopen("inversmodular.out","w",stdout);

    long long a,b,x,y;
    scanf("%lld%lld",&a,&b);
    euclid(a,b,x,y);
    printf("%d",(x+b)%b);

    return 0;
}