#define DEBUG 0
#include <bits/stdc++.h>
using namespace std;
#if DEBUG
// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}
// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
public:
template<typename T>
_Debug& operator,(T val) {
cout << val << endl;
return *this;
}
};
#define debug _Debug(),
#else
#define printLine(l)
#define printLine2(l,c)
#define printVar(n)
#define printArr(a,l)
#define print2dArr(a,r,c)
#define print2dArr2(a,r,c,l)
#define debug
#endif
// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6
#define mp make_pair
#define pb push_back
// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;
// ---------- END OF TEMPLATE ----------
int N,A[100000],B[100000],C[100000];
int num[200000];
pii order[100000];
int main() {
int i;
int M;
LLI ans = 0;
scanf("%d %d",&N,&M);
for (i = 0; i < M; i++) {
scanf("%d %d %d",&A[i],&B[i],&C[i]);
if (!(C[i] & 1)) ans += C[i]/2,i--,M--;
else {
if (A[i] > B[i]) swap(A[i],B[i]);
}
}
LLI ans2 = 1e9;
for (i = 0; i < N; i++) {
int j,k;
fill(num,num+N,0);
for (j = 0; j < M; j++) {
A[j] = (A[j]+1) % N,B[j] = (B[j]+1) % N;
if (A[j] > B[j]) swap(A[j],B[j]);
for (k = A[j]; k < B[j]; k++) num[k]--;
order[j] = mp(B[j],j);
}
int a = M;
sort(order,order+M);
for (j = 0; j < M; j++) {
int u = order[j].second;
for (k = A[u]; k < B[u]; k++) {
if (num[k]+2 > 0) break;
}
if (k == B[u]) {
for (k = A[u]; k < B[u]; k++) num[k] += 2;
a--;
}
}
ans2 = min(ans2,(LLI) a);
}
printf("%lld\n",ans+ans2);
return 0;
}
