//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<sstream>
#include<cmath>
#include<climits>
#include<string>
#include<map>
#include<queue>
#include<vector>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define pb(a) push(a)
#define INF 0x1f1f1f1f
#define lson idx<<1,l,mid
#define rson idx<<1|1,mid+1,r
#define PI  3.1415926535898
template<class T> T min(const T& a,const T& b,const T& c) {return min(min(a,b),min(a,c));
}
template<class T> T max(const T& a,const T& b,const T& c) {return max(max(a,b),max(a,c));
}
void debug() {
#ifdef ONLINE_JUDGE
#elsefreopen("d:\\in1.txt","r",stdin);freopen("d:\\out1.txt","w",stdout);
#endif
}
int getch() {int ch;while((ch=getchar())!=EOF) {if(ch!=' '&&ch!='\n')return ch;}return EOF;
}struct Edge
{int from,to,dist;
};
struct HeapNode
{int d,u;bool operator < (const HeapNode &ant ) const{return d>ant.d;}
};const int maxn=1005;
int n;
vector<int> g[maxn];
vector<Edge> edge;void InitGraph()
{for(int i=1;i<=n;i++)g[i].clear();edge.clear();
}void AddEdge(int u,int v,int w)
{Edge e=(Edge){u,v,w};edge.push_back(e);g[u].push_back(edge.size()-1);
}int done[maxn];
int d[maxn];void Dijksta(int s)
{priority_queue<HeapNode> q;q.push((HeapNode){0,s});for(int i=1;i<=n;i++)d[i]=INF;d[s]=0;memset(done,0,sizeof(done));while(!q.empty()){HeapNode x=q.top();q.pop();if(done[x.u])continue;done[x.u]=1;for(int i=0;i<g[x.u].size();i++){Edge &e=edge[g[x.u][i]];if(d[e.to]>d[x.u]+e.dist){d[e.to]=d[x.u]+e.dist;q.push((HeapNode){d[e.to],e.to});}}}
}int dp[maxn];
int f(int u)
{if(u==2)return 1;if(dp[u]>=0)return dp[u];dp[u]=0;for(int i=0;i<g[u].size();i++){int v=edge[g[u][i]].to;if(d[v]<d[u])dp[u]+=f(v);}return dp[u];
}
int DP()
{memset(dp,-1,sizeof(dp));return f(1);
}int main()
{while(scanf("%d",&n)!=EOF&&n){InitGraph();int m;scanf("%d",&m);for(int i=1;i<=m;i++){int u,v,w;scanf("%d%d%d",&u,&v,&w);AddEdge(u,v,w);AddEdge(v,u,w);}Dijksta(2);int res=DP();printf("%d\n",res);}return 0;
}