#include <cstdio>
#include <algorithm>
#include <vector>
using namespace std;
const int max1 = 1000, max2 = 2e4, front = 25;
const double inf = 0x3f3f3f3f3f3f3f3f;
int n, m, k, x, y, P[max2 + front + 5], sum[max2 + front + 5];
struct Edge
{
    int v, w, A, B;
    Edge () {}
    Edge ( int __v, int __w, int __A, int __B )
        { v = __v, w = __w, A = __A, B = __B; }
};
vector <Edge> edge[max1 + 5];
double f[max1 + 5][front + 5][2], val[front + 5], g[front + 5];
pair <double, double> h[front + 5];
int main ()
{
    scanf("%d%d%d%d%d", &n, &m, &k, &x, &y);
    for ( int i = 1, u, v, w, A, B; i <= m; i ++ )
    {
        scanf("%d%d%d%d%d", &u, &v, &w, &A, &B);
        edge[u].push_back(Edge(v, w, A, B));
        edge[v].push_back(Edge(u, w, A, B));
    }
    for ( int i = 1, T, w; i <= k; i ++ )
        { scanf("%d%d", &T, &w); P[T] = sum[T] = w; }
    for ( int i = max2 + front; i >= 0; i -- )
        sum[i] += sum[i + 1];
    int now = 0;
    for ( int i = 1; i <= n; i ++ )
        for ( int T = 0; T < front; T ++ )
            f[i][T][0] = f[i][T][1] = inf;
    for ( int T = 0; T < front; T ++ )
        f[y][T][0] = f[y][T][1] = 0;
    for ( int T = max2; T >= 0; T -- )
    {
        now = ( now + front - 1 ) % front;
        for ( int i = 1; i <= n; i ++ )
            f[i][now][0] = f[i][now][1] = inf;
        f[y][now][0] = f[y][now][1] = 0;
        for ( int i = 1; i <= front; i ++ )
        {
            val[i] = 1;
            g[i] = 0;
            h[i] = make_pair(0, 0);
            for ( int j = 1; j <= i; j ++ )
            {
                if ( P[T + j] )
                {
                    g[i] += val[i] * P[T + j] / sum[T + j];
                    h[i].first += val[i] * P[T + j] / sum[T + j] * j;
                    h[i].second += val[i] * P[T + j] / sum[T + j] * ( i - j );
                    val[i] = val[i] * ( 1.0 - 1.0 * P[T + j] / sum[T + j] );
                }
            }
        }
        for ( int i = 1; i <= n; i ++ )
        {
            if ( i == y )
                continue;
            for ( auto Tmp : edge[i] )
            {
                int v = Tmp.v, w = Tmp.w, A = Tmp.A, B = Tmp.B;
                f[i][now][0] = min(f[i][now][0], val[w] * ( f[v][( now + w ) % front][0] + w * A ) + g[w] * f[v][( now + w ) % front][1] + h[w].first * A + h[w].second * B);
                f[i][now][1] = min(f[i][now][1], w * B + f[v][( now + w ) % front][1]);
            }
        }
    }
    printf("%.10lf\n", f[x][now][0]);
    return 0;
}