# include <math.h>

# include <stdio.h>

# include <string.h>

# include <algorithm>

// # include <bits/stdc++.h>

using namespace std;

typedef long long ll;

typedef long double ld;

typedef unsigned long long ull;

const int M = 5e5 + ;

const int mod = 1e9+;

# define RG register

# define ST static

int T, n, m;

int head[M], nxt[M], to[M], tot;

ld w[M];

inline void add(int u, int v, ld _w) {

    ++tot; nxt[tot] = head[u];

    head[u] = tot; to[tot] = v; w[tot] = _w;

}

bool vis[M];

ld v[M];

inline bool dfs(int x, ld c) {

    v[x] = c; vis[x] = ;

    for (int i=head[x]; i; i=nxt[i]) {

        if(!vis[to[i]]) {

            if(dfs(to[i], c*w[i])) return ;

        } else {

            if(fabs(v[to[i]]-c*w[i]) > 1e-) return ;

        }

    }

    return ;

}

inline void sol() {

    memset(head, , sizeof head);

    tot = ;

    scanf("%d%d", &n, &m);

    for (int i=; i<=m; ++i) {

        int u, v, x, y; scanf("%d%d%d%d", &u, &v, &x, &y);

        add(u, v, (ld)y/x);

        add(v, u, (ld)x/y);

    }

    memset(vis, , sizeof vis);

    for (int i=; i<=n; ++i) {

        if(vis[i]) continue;

        if(dfs(i, )) {

            puts("No");

            return;

        }

    }

    puts("Yes");

}

int main() {

    int T; scanf("%d", &T);

    for (int i=; i<=T; ++i) {

        printf("Case #%d: ", i);

        sol();

    }

    return ;

}