#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"
template<class T> bool minimize(T &a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> bool maximize(T &a, T b) { if (a < b) { a = b; return 1; } return 0; }
void setIO() {
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(file".inp", "r")) {
freopen(file".inp", "r", stdin);
freopen(file".out", "w", stdout);
}
}
const int N = 2e5+5;
int n, m, a[N], b[N], c[N];
int cnt[N];
int mx;
void inc(int l, int r, bool t) {
if (l > r) swap(l, r);
if (!t) foru(i, l, r-1) maximize(mx, ++cnt[i]);
else {
foru(i, 1, l-1) maximize(mx, ++cnt[i]);
foru(i, r, n) maximize(mx, ++cnt[i]);
}
}
int main() {
setIO();
cin >> n >> m;
foru(i, 1, m) {
cin >> a[i] >> b[i] >> c[i];
}
foru(i, 1, m) {
while (c[i]-->1) {
++m;
a[m] = a[i];
b[m] = b[i];
}
}
int mn = N;
for(int mask=0; mask<(1<<m); ++mask) {
foru(i, 1, n) cnt[i] = 0;
mx = 0;
foru(i, 1, m)
if (mask >> (i-1) & 1) {
inc(a[i], b[i], 0);
}
else {
inc(a[i], b[i], 1);
}
minimize(mn, mx);
}
cout << mn;
}
