#include<cstdio>

#include<cstring>

#include<algorithm>

#include<map>

#include<iostream>

#include<vector>

#include<string>

#include<cmath>

#include<set>

using namespace std;

typedef long long ll;

typedef unsigned long long ull;

const int N = +;

struct exam{

    int b;

    int s;

    int d;

    int c;

}e[N];

bool cmp(exam& a,exam& b){

    return a.d < b.d;

}

int ans[N];

int main(void){

    int n,m;

    memset(ans,,sizeof(ans));

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

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

        scanf("%d%d%d",&e[i].s,&e[i].d,&e[i].c);

        e[i].b = i;

    }

    sort(e+,e+m+,cmp);

    int ok = ;

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

        if(ok){

            for(int j=e[i].s;;j++){

                if(j == e[i].d && e[i].c != ){

                    ok = ;

                    printf("-1");

                    break;

                }

                if(e[i].c == ){

                    ans[e[i].d] = m+;

                    break;

                }

                if(ans[j] == ){

                    ans[j] = e[i].b;

                    e[i].c--;

                }

            }

        }

    }

    if(ok){

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

            printf("%d",ans[i]);

            if(i != n){

                printf(" ");

            }

        }

    }

    return ;

}