#include <bits/stdc++.h>
using namespace std;
long long n,m,a[1000005],b[1000005],c[100005],x,y,z,ans;
int main(){
	cin>>n>>m;
	for(long long i=1;i<=m;i++){
		cin>>x>>y>>z;
		if(z==1){
			a[x]++;
			a[y+1]--;
		}
		if(z==2){
			b[x]++;
			b[y+1]--;
		}
		if(z==3){
			c[x]++;
			c[y+1]--;
		}
	}
	for(long long i=1;i<=n;i++){
	    a[i]+=a[i-1];
		b[i]+=b[i-1];
		c[i]+=c[i-1];
		if(a[i]>0&&b[i]>0&&c[i]==0){
			ans++;
		}
	}
	cout<<ans<<endl;
	return 0;
}