#include <cstdio>

void euclid_eXt(int a, int b, int c, int &x, int &y)
{
    int q[100], x0, y0, r, p=0;
    while(b != 0)
    {
        r = a%b;
        q[++p] = a/b;
        a=b;
        b=r;
    }
    if(c%a) {x=y=0;return;}
    x=x0 = c/a;
    y=y0 = 0;
    while(p)
    {
        x= y0;
        y = x0 - (q[p--]*y0);
        x0 = x;
        y0 = y;
    }
}

int main()
{
    FILE *f =fopen("inversmodular.in", "r");
    FILE *g =fopen("inversmodular.out", "w");
    int t, a, b,c ,x, y;

    fscanf(f, "%d%d", &a, &b);
    euclid_eXt(a, b, 1, x, y);
    x=((long long)b+x%b)%b;
    fprintf(g, "%d", x);
    return 0;
}