#include<bits/stdc++.h>

#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define ll long long
#define pii pair<int,int>
#define pill pair<int,ll>
#define pll pair<ll,ll>
#define pb push_back
#define fi first
#define se second
#define ff fi.fi
#define fs fi.se
#define sf se.fi
#define ss se.se
#define MASK(x) (((1)<<(x))-1)
#define getbit(x,k) (((x)>>(k))&1)

using namespace std;

const int maxn=1e5+50,mod=1e17+9;
const ll inf=0x3f3f3f3f3f3f3f3f;

int n,m;
vector<pii>eg[maxn];
ll d1[maxn],dn[maxn];
ll w1[maxn],wn[maxn];

void dijkstra(ll d[], ll w[], int st)
{
    memset(d,0x3f,(n+10)*sizeof(ll));d[st]=0;
    priority_queue<pll,vector<pll>,greater<pll>>pQ;
    pQ.push({d[st],st});
    w[st]=1;
    while(pQ.size())
    {
        pll u=pQ.top();pQ.pop();
        if(u.fi!=d[u.se]) continue;
        for(pii v:eg[u.se])
        {
            if(u.fi+v.se<d[v.fi])
            {
                d[v.fi]=u.fi+v.se;
                w[v.fi]=w[u.se];
                pQ.push({d[v.fi],v.fi});
            }
            else if(u.fi+v.se==d[v.fi])
                w[v.fi]=(w[v.fi]+w[u.se])%mod;
        }
    }
}
ll nad(ll a, ll b)
{
    ll rs=0;
    while(b)
    {
        if(b&1) rs=(rs+a)%mod;
        a=(a+a)%mod;
        b>>=1;
    }
    return rs;
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int u,v,c;cin>>u>>v>>c;
        eg[u].pb({v,c});eg[v].pb({u,c});
    }
    dijkstra(d1,w1,1);dijkstra(dn,wn,n);
    int ans=0;
    for(int u=1;u<=n;u++)
        for(pii v:eg[u])
            if(d1[u]+dn[v.fi]+v.se==d1[n])
                if(nad(w1[u],wn[v.fi])==w1[n])
                    ans++;
    cout<<ans;
}