#include<stdio.h>
#include<algorithm>
using std::sort;

int n,m,ans[100002];
struct P{ int l,r,id; }a[100002];

inline bool in(int p,P a){ return a.l<a.r?a.l<=p&&p<a.r:a.r<=p&&p<=a.l+n; }
inline int len(P a){ return a.l<a.r?a.r-a.l:a.r+n-a.l; }

inline int min(int x,int y){ return x<y?x:y; }
inline int max(int x,int y){ return x>y?x:y; }

int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++) scanf("%d%d",&a[i].l,&a[i].r),a[i].l--,a[i].r--,((++a[i].r)%=n),a[i].id=i;//,printf("debug: %d %d\n",a[i].l,a[i].r);
    int p=1;
    for(int i=1;i<=m;i++) if(/*printf("debug: %d\n",len(a[i])),*/len(a[i])>len(a[p])) p=i;
    int s=a[p].l;
    //printf("s: %d, [%d,%d)\n",s,a[p].l,a[p].r);
    for(int i=1;i<=m;i++) a[i].l=(a[i].l-s+n)%n,a[i].r=(a[i].r-s+n)%n,(a[i].l>=a[i].r)&&(a[i].r+=n);//,printf("%d %d %d\n",a[i].l,a[i].r,a[i].id);
    sort(a+1,a+m+1,[](P a,P b){ return a.l==b.l?a.r>b.r:a.l<b.l; });
    int q=0;
    for(int i=2;i<=m;i++) if(a[i].r>=n&&(!q||a[i].l<a[q].l)) q=i;
    if(!q) return printf("impossible"),0;
    //case p!=q
    bool flag=0;
    int x=a[1].r,y=a[q].r-n,type=0;//type of x
    ans[a[1].id]=0,ans[a[q].id]=1;
    //printf("[%d,%d) [%d,%d)\n",a[1].l,a[1].r,a[q].l,a[q].r);
    for(int i=2;i<=m;i++)
    {
        //printf("now: [%d,%d) id %d, 0: %d, 1: %d\n",a[i].l,a[i].r,a[i].id,type?y:x,type?x:y);
        if(a[i].l<=min(x,y))
        {
            if(i!=q)
                if(a[i].r>x) y=x,x=a[i].r,ans[a[i].id]=(type^=1);//,printf("choose %d\n",type);
                else if(a[i].r>y) y=a[i].r,ans[a[i].id]=(type^1);//,printf("choose %d\n",type^1);
                else ans[a[i].id]=0;
            else type?(x=a[q].r):(y=a[q].r);
            if(x>=n&&y>=n){ flag=1;break; }
        }
        else break;
    }
    //printf("last: 0: %d, 1: %d\n",type?y:x,type?x:y);
    if(flag)
    {
        for(int i=1;i<=m;i++) printf("%d",ans[i]);
        printf("\n");
        return 0;
    }
    //printf("?");
    int r=0;
    for(int i=2;i<=m;i++) if(i!=q&&a[i].r>=n&&a[q].l<=a[i].l&&a[i].r-n<=a[1].r) r=i;
    if(!r) return printf("impossible"),0;
    x=a[1].r,y=a[r].r-n,type=0;
    ans[a[1].id]=ans[a[q].id]=0,ans[a[r].id]=1;
    for(int i=2;i<=m;i++)
    {
        //printf("now: [%d,%d) id %d, 0: %d, 1: %d\n",a[i].l,a[i].r,a[i].id,type?y:x,type?x:y);
        if(a[i].l<=min(x,y))
        {
            if(i!=q&&i!=r)
                if(a[i].r>x) y=x,x=a[i].r,ans[a[i].id]=(type^=1);//,printf("choose %d\n",type);
                else if(a[i].r>y) y=a[i].r,ans[a[i].id]=(type^1);//,printf("choose %d\n",type^1);
                else ans[a[i].id]=0;
            else if(i==q) type?(y=a[q].r):(x=a[q].r);
            else if(i==r) type?(x=a[r].r):(y=a[r].r);
            if(x>=n&&y>=n){ flag=1;break; }
        }
        else break;
    }
    if(flag)
    {
        for(int i=1;i<=m;i++) printf("%d",ans[i]);
        printf("\n");
    }
    else printf("impossible");
    /*static bool f[100002][2];
    for(int i=1;i<=m;i++)
        for(int j=a[i].l;j<a[i].r;j++) f[j%n][ans[a[i].id]]=1;
    for(int i=0;i<n;i++) if(!(f[i][0]&&f[i][1])) printf("? %d %d %d\n",i,f[i][0],f[i][1]);*/
    return 0;
}