#include<bits/stdc++.h>
using namespace std;
const int N=1010;
struct node{
	int l,r,t;
}e[N];
int n;
bool cmp(node a,node b){
	return a.r<b.r;
}
int a[N];
int main(){
freopen("tower.in","r",stdin);
freopen("tower.out","w",stdout);
cin >> n;
for(int i=1;i<=n;i++) cin >> e[i].l >> e[i].r >> e[i].t;
sort(e+1,e+1+n,cmp);
int ans=0;
for(int i=1;i<=n;i++){
	int cnt=e[i].t;
	for(int j=e[i].l;j<=e[i].r;j++)
	if(a[j])cnt--;
	int pos=e[i].r;
	  for(int j=1;j<=cnt;j++){
	  	while(a[pos]) pos--;
	  	a[pos]=1;
	  	pos--;
	  	ans++;
	  }
		
}
cout << ans;
  return 0;
}


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