#include<iostream>

#include<cstdio>

#include<cstring>

#include<string>

#include<algorithm>

#include<cctype>

#include<cmath>

#include<cstdlib>

#include<queue>

#include<ctime>

#include<vector>

#include<set>

#include<map>

#include<stack>

using namespace std;

const long long inf = 1e12+;

struct node {

    long long t1,t2,sum;

};

node wh[];

long long d[];

inline bool cmp(const node x,const node y){

       if(x.t1==y.t1)return x.t2<y.t2;

       return x.t1<y.t1;

}

inline void build(long long le,long long ri,long long wh,long long pl,long long k){

      if(le==ri){

          d[wh]=k;

          return;

      }

      long long mid=(le+ri)>>;

      if(mid>=pl)build(le,mid,wh<<,pl,k);

        else build(mid+,ri,wh<<|,pl,k);

      d[wh]=min(d[wh<<],d[wh<<|]);

      return;

}

inline long long q(long long le,long long ri,long long wh,long long x,long long y){

      if(le>=x&&ri<=y){

          return d[wh];

      }

      long long mid=(le+ri)>>,ans=inf;

      if(mid>=x)ans=min(ans,q(le,mid,wh<<,x,y));

      if(mid<y)ans=min(ans,q(mid+,ri,wh<<|,x,y));

      return ans;

}

int main(){

      long long n,s,t,i,j,k;

      scanf("%lld%lld%lld",&n,&s,&t);

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

          scanf("%lld%lld%lld",&wh[i].t1,&wh[i].t2,&wh[i].sum);

          wh[i].t1+=;

          wh[i].t2+=;

          wh[i].t1-=s;

          wh[i].t2-=s;

      }

      t=(t-s)+,s=;

      build(,t,,,);

      for(i=s;i<=t;i++)

        build(,t,,i,inf);

      sort(wh+,wh+n+,cmp);

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

          long long x=min(q(,t,,wh[i].t2,wh[i].t2),

                  q(,t,,wh[i].t1-,wh[i].t2-)+wh[i].sum);

          build(,t,,wh[i].t2,x);

      }

      long long x=q(,t,,t,t);

      if(x>=inf)x=-;

      printf("%lld\n",x);

      return ;

}