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#pragma GCC optimize("Ofast")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define e1 first
#define e2 second
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define ld long double
#define float long double
#define size(x) (int)x.size()
#define satori int testCases; cin>>testCases; while(testCases--)
#define fastio ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define all(r) begin(r),end(r)
#define time chrono::high_resolution_clock().now().time_since_epoch().count()
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
mt19937 rng(chrono::high_resolution_clock().now().time_since_epoch().count());
///////////////////
#define debug if(1)
///////////////////

const int MAXN=1e6+10;

int p[3][MAXN];

int32_t main()
{
	fastio;
	int n,m,k,l,r;
	cin>>n>>m;
	while(m--){
		cin>>l>>r>>k;
		p[k-1][l]++;
		p[k-1][r+1]--;
	}
	int result=0;
	for(int i=1;i<=n;i++){
		for(int j=0;j<3;j++)
			p[j][i]+=p[j][i-1];
		if(p[0][i]>0&&p[1][i]>0&&p[2][i]==0)
			result++;
	}
	cout<<result<<'\n';
}