#include <stdio.h>
    #include <stdlib.h>
    #include <bits/stdc++.h>

    //type definitions
    #define rep(a,b) for(int i=a;i<=b;i++)
    #define rev(a,b) for(int i=a;i>=b;i--)
    #define mem(a,b) memset(a,b,sizeof(a))
    #define SET(a) memset(a,-1,sizeof a)
    #define CLR(a) memset(a,0,sizeof a)
    #define all(a) a.begin(),a.end()
    #define in(n) scanf("%d",&n)
    #define out(n) printf("%d",n)
    #define mark(mask ,i) (mask|(1 << i))
    #define ismarked(mask ,i) (mask & (1 << i))

    ///STL
    #define vi vector<int>
    #define vvi vector< vector<int> >
    #define pb push_back
    #define mp make_pair
    #define mii map<int,int>
    #define pii pair<int,int>
    #define f first
    #define s second

    //Iterator!
    #define forit(it, s) for(__typeof(s.begin()) it = s.begin(); it != s.end(); it++)

    /// Constants
    # define MAX_CHAR  26;
    #define LINF 1e18 + 7
    #define INF 1000000000
    #define ll long long
    #define mod 1000000007
    #define EPS 1e-9
    #define sqr(x) ((x)*(x))
    #define sqrt(x) sqrt(1.0*(x))
    /// Files.
    #define READ(f) freopen(f, "r", stdin)
    #define WRITE(f) freopen(f, "w", stdout)
    #define ios std::ios::sync_with_stdio(false);

    using namespace std;

    int main()
    {
        int n ,m;
        cin >> n >> m;
        if(n % m == 0)
        {
            cout << 0;
            return 0;
        }
        double tot = 1.0 * n;
        double x = (1.0 * n) / ((1.0) * m);
        int ans = 0;
        if(n > m)
        {
            double t = 0.0;
            while(1)
            {
                t += x;
                if(fabs(t - round(t)) > EPS)
                    ans++;
                if(fabs(t - tot) < EPS)
                    break;


            }
        }
        else
        {
            double t = 0.0;
            while(1)
            {
                t += x;
                if(fabs(round(t) - t) > EPS)
                    ans++;
                if(fabs(t - tot) < EPS)
                   break;

            }
        }
        cout << ans << endl;
        return 0;
    }