#include<cstdio>

#include<algorithm>

#include<cstring>

#include<iostream>

#include<cctype>

#include<cmath>

#include<set>

#include<map>

#include<vector>

#include<queue>

#include<bitset>

#define pa pair<double,int>

#define fore(i, u, v) for (int i = head[u], v = e[i].to; i; i = e[i].nxt, v = e[i].to)

using namespace std;

typedef long long LL;

inline int read() {

    int x=,f=;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-;

    for(;isdigit(ch);ch=getchar())x=x*+ch-'';return x*f;

}

const int N = ;

struct Edge { int to, nxt; double w; } e[N << ];

int head[N], En, n, m;

double P[N], dp[N], sp[N], s[N], tp[N];

bool vis[N];

inline void add_edge(int u,int v,int w) {

    ++En; e[En].to = v, e[En].w = 1.0 * w / 100.0, e[En].nxt = head[u]; head[u] = En;

}

void Dijkstra() {

    priority_queue< pa, vector< pa >, greater< pa > > q;

    for (int i = ; i <= n; ++i) dp[i] = 1e18, tp[i] = 1.0;

    q.push(pa(, n)); dp[n] = ;

    while (!q.empty()) {

        int u = q.top().second; q.pop();

        if (vis[u]) continue; vis[u] = ;

        fore(i, u, v) {

            double sum = s[v] + dp[u] * e[i].w * tp[v];

            double sump = sp[v] + e[i].w * tp[v];

            if (dp[v] > (sum + 1.0) / sump) {

                dp[v] = (sum + 1.0) / sump;

                s[v] += dp[u] * e[i].w * tp[v];

                sp[v] += e[i].w * tp[v];

                tp[v] *= ( - e[i].w);

                q.push(pa(dp[v], v));

            }

        }

    }

    printf("%.3lf\n", dp[]);

}

int main() {

    n = read(), m = read();

    for (int u, v, w, i = ; i <= m; ++i)

        u = read(), v = read(), w = read(), add_edge(v, u, w);

    Dijkstra();

    return ;

}