#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL brute(vector<vector<LL> > z, LL n){
LL best = z.size();
for(LL r = 0; r < (1 << z.size()); r++){
vector<LL> freq(n,0);
for(int j = 0; j < z.size(); j++){
LL c = z[j][0];
LL d = z[j][1];
if(r & (1 << j)){
swap(c,d);
}
while(c != d){
freq[c]++;
c++;
c %= n;
}
}
LL maxused = 0;
for(int j = 0; j < n; j++){
maxused = max(maxused, freq[j]);
}
best = min(best, maxused);
}
return best;
}
LL two(vector<vector<LL> > z, LL n){
LL bound = 0;
vector<int> a(2);
for(a[0] = 0; a[0] < n; a[0]++){
for(a[1] = 0; a[1] < n; a[1]++){
LL cross = 0;
for(int j = 0; j < z.size(); j++){
int parity = 0;
LL c = z[j][0];
LL d = z[j][1];
while(c != d){
if(c == a[0] || c == a[1]) parity ^= 1;
c++;
c %= n;
}
cross += parity;
}
bound = max(bound, (cross+1)/2);
}
}
return bound;
}
int main(){
cin.sync_with_stdio(0); cin.tie(0);
LL n, m;
cin >> n >> m;
// stations 1 to n
vector<vector<LL> > z;
for(int i = 0; i < m; i++){
LL a, b, c;
cin >> a >> b >> c;
a--; b--;
for(int j = 0; j < c; j++){
z.push_back(vector<LL>({a,b}));
}
}
LL bound = two(z, n);
LL ans = brute(z, n);
assert(ans <= bound);
assert(bound - 1 <= ans);
cout << ans << '\n';
}
