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#include <bits/stdc++.h>
 
using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef long long LL;
typedef pair<int,int> PI; 
typedef pair<LL,LL> PLL;
typedef unsigned long long ULL;
typedef pair<double,double> PD;
 
#define FOR(x, b, e) for(int x = b; x<= (e); x++)
#define FORD(x, b, e) for(int x = b; x>= (e); x--)
#define REP(x, n) for(int x = 0; x<(n); ++x)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
 
#define PB push_back
#define IN insert
#define ST first
#define ND second
#define INF 2000000011
#define MOD 1000000007
 
#define MAXS 3000010

int kolory[MAXS];
int szer=1;

void add(int v,int a,int b,int l ,int r,int val){
    if(a==l&&b==r){
        kolory[v]|=val;
        return;
    }
    int mid=(a+b-1)/2;
    if(r<=mid)
        add(v*2,a,mid,l,r,val);
    else if(mid<l)
        add(v*2+1,mid+1,b,l,r,val);
    else{
        add(v*2,a,mid,l,mid,val);
        add(v*2+1,mid+1,b,mid+1,r,val);
    }
}

int query(int x){
    x+=szer;
    int val=0;
    while(x){
        val|=kolory[x];
        x/=2;
    }
    return val;
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n,m;
    cin>>n>>m;

    while(szer<n)
        szer*=2;
    
    while(m--){
        int l,r,val;
        cin>>l>>r>>val;
        l--;r--;val--;

        add(1,0,szer-1,l,r,1<<val);
    }


    int count=0;
    REP(i,n){
        if(query(i)==3)
            count++;
    }

    cout<<count<<"\n";
}