#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N=200050;
const int M=2*N;
const int inf=1e9+7;
int ls[M],rs[M],tsz,root,lzy[M],mx[M];
void Add(int &c, int ss, int se, int qs, int qe, int f)
{
if(qs>qe || qs>se || ss>qe) return;
if(!c) c=++tsz;
if(qs<=ss && qe>=se){ lzy[c]+=f;mx[c]+=f;return;}
int mid=ss+se>>1;
Add(ls[c],ss,mid,qs,qe,f);
Add(rs[c],mid+1,se,qs,qe,f);
mx[c]=max(mx[ls[c]],mx[rs[c]])+lzy[c];
}
int Get(int c, int ss, int se, int qs, int qe)
{
if(qs>qe || qs>se || ss>qe) return -inf;
if(qs<=ss && qe>=se) return mx[c];
int mid=ss+se>>1;
return max(Get(ls[c],ss,mid,qs,qe),Get(rs[c],mid+1,se,qs,qe))+lzy[c];
}
void init()
{
for(int i=1;i<=tsz;i++) ls[i]=rs[i]=lzy[i]=mx[i]=0;
tsz=root=0;
}
int a[N],b[N],c[N],n,m;
ll Solve()
{
init();
int i;
ll ans=0;
for(i=1;i<=m;i++)
{
ans+=c[i]/2;
if(a[i]>b[i]) swap(a[i],b[i]);
if(c[i]&1) Add(root,1,n,a[i],b[i]-1,1);
}
for(i=1;i<=m;i++) if(c[i]&1)
{
int pre=mx[root],nxt=max(Get(root,1,n,1,a[i]-1),Get(root,1,n,b[i],n))+1;
if(pre>nxt) Add(root,1,n,1,n,1),Add(root,1,n,a[i],b[i]-1,-2);
}
ans+=mx[root];
return ans;
}
ll Brute()
{
ll sum=0,ans=inf;
for(int i=1;i<=m;i++){ if(a[i]>b[i]) swap(a[i],b[i]);sum+=c[i]/2;}
for(int mask=0;mask<(1<<m);mask++)
{
init();
for(int i=1;i<=m;i++) if(c[i]&1)
{
if((mask>>(i-1))&1)
{
Add(root,1,n,a[i],b[i]-1,1);
}
else
{
Add(root,1,n,1,n,1);
Add(root,1,n,a[i],b[i]-1,-1);
}
}
ans=min(ans,(ll)mx[root]);
}
return sum+ans;
}
void input()
{
scanf("%i %i",&n,&m);
for(int i=1;i<=m;i++) scanf("%i %i %i",&a[i],&b[i],&c[i]);
}
void Test()
{
srand(time(0));
int t=10000;
for(int i=1;i<=t;i++)
{
n=rand()%3+2;
m=rand()%5+1;
for(int j=1;j<=m;j++)
{
do
{
a[j]=rand()%n+1;
b[j]=rand()%n+1;
}while(a[j]==b[j]);
c[j]=rand()%100+1;
}
ll sol=Solve();
ll bru=Brute();
if(sol!=bru)
{
printf("%i %i\n",n,m);
for(int j=1;j<=m;j++) printf("%i %i %i\n",a[j],b[j],c[j]);
printf("Solve: %lld\n",sol);
printf("Brute: %lld\n",bru);
return;
}
printf("%i OK\n",i);
}
}
int main()
{
//Test();
input();
printf("%lld\n",Brute());
return 0;
}
