#include <iostream>

#include <cstdio>

#include <algorithm>

using namespace std;

const int N=1e5+10;

struct Guard {

    int a,b,c;

}g[N];

int n,k,m,zm,gcnt;

int zer[N],ref[N],rcnt,nearl[N],nearr[N],f[N],h[N];

bool ans;

bool CMP(Guard a,Guard b) {return a.a<b.a;}

int main() {

    scanf("%d%d%d",&n,&k,&m);

    for (int i=1;i<=m;i++) {

        scanf("%d%d%d",&g[i].a,&g[i].b,&g[i].c);

        if (!g[i].c) zer[g[i].a]++,zer[g[i].b+1]--;

    }

    for (int i=1;i<=n;i++) {

        zer[i]+=zer[i-1];

        if (!zer[i]) ref[nearl[i]=nearr[i]=++rcnt]=i;

        else nearl[i]=n+1;

    }

    if (rcnt==k) {for (int i=1;i<=rcnt;i++) printf("%d\n",ref[i]);return 0;}

    for (int i=2;i<=n;i++) nearr[i]=max(nearr[i],nearr[i-1]),nearl[n-i+1]=min(nearl[n-i+1],nearl[n-i+2]);

    for (int i=1;i<=m;i++) if (g[i].c&&nearl[g[i].a]<=nearr[g[i].b]) g[++zm].a=nearl[g[i].a],g[zm].b=nearr[g[i].b];

    sort(g+1,g+zm+1,CMP);

    for (int i=1;i<=zm;i++) {

        while (gcnt&&g[gcnt].a<=g[i].a&&g[i].b<=g[gcnt].b) gcnt--;

        g[++gcnt]=g[i];

    }

    for (int i=1,r=0;i<=gcnt;i++) if (g[i].a>r) f[i]=f[i-1]+1,r=g[i].b; else  f[i]=f[i-1];

    for (int i=gcnt,l=n+1;i;i--) if (g[i].b<l) h[i]=h[i+1]+1,l=g[i].a; else h[i]=h[i+1];

    for (int i=1,l,r,mid,ansl,ansr;i<=gcnt;i++)

        if (f[i]!=f[i-1])

            if (g[i].a==g[i].b) printf("%d\n",ref[g[i].b]),ans=1;

            else {

                l=1;r=i-1;ansl=0;

                while (l<=r) {

                    mid=l+r>>1;

                    if (g[mid].b<g[i].b-1) l=mid+1,ansl=mid; else r=mid-1;

                }

                l=i+1;r=gcnt;ansr=n+1;

                while (l<=r) {

                    mid=l+r>>1;

                    if (g[mid].a>g[i].b-1) r=mid-1,ansr=mid; else l=mid+1;

                }

                if (f[ansl]+1+h[ansr]>k) printf("%d\n",ref[g[i].b]),ans=1;

            }

    if (!ans) printf("-1\n");

}