2006 resp, 1-1

#include <cstdio>
#define ll long long
#define forn(i,n) for(int i=1;i<=n;i++)

ll pows[20],f,k,a,b,t;

void input(){
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    scanf("%I64d%I64d",&f,&k);pows[0]=1;
    forn(i,18) pows[i]=pows[i-1]*10ll;
    ll q=f;
    while (q){
        q/=10ll;
        ++t;
    }
}

ll gcd (ll a,ll b,ll &x,ll &y){
    if (a==0ll){
        x=0ll;y=1ll;
        return b;
    }
    ll x1,y1;
    ll g=gcd(b%a,a,x1,y1);
    x=y1-(b/a)*x1;
    y=x1;
    return g;
}

ll len(ll x){
    ll ans=0;
    while (x){
        x/=10ll;
        ++ans;
    }
    return ans?ans:1;
}

void sol(){
    for(int _=0;_<2;_++,t--){
        a=pows[k]+1ll;b=pows[t]-1ll;
        ll x,y;
        ll g=gcd(a,b,x,y);
        if (f%g!=0) continue;
//      x*=f/g;
//      if (x<0) x+=-x*(b/g);
//      x%=b/g;
        x=((x%(b/g))*((f/g)%(b/g)))%(b/g);
        y=(f-a*x)/b;
        for(;;){
            if (-y==x/pows[t-k] && len(x)==t){
                printf("%I64d\n",x);
                return;
            }
            x+=b/g;
            y-=a/g;
            if (x>f) break;
        }
    }
}

int main(){
    input();
    sol();
    return 0;
}