#include <cstdio>

#include <algorithm>

using namespace std;

const int MAXN = ;

const int MAXM = ;

int cnt=,u[MAXM],v[MAXM],w[MAXM],first[MAXN],next[MAXM];

int dis[MAXN],st,ans=,n,fa[MAXN];

inline int qread(void){

    int x=;

    char s;

    s=getchar();

    while(s>''||s<'')

        s=getchar();

    while(s>=''&&s<=''){

        x*=;

        x+=s-'';

        s=getchar();

    }

    return x;

}

inline void qwrite(int x){

    if(x>){

    qwrite(x/);

    }

    putchar(x%+'');

}

void addedge(int ux,int vx,int wx){

    ++cnt;

    u[cnt]=ux;

    v[cnt]=vx;

    w[cnt]=wx;

    next[cnt]=first[ux];

    first[ux]=cnt;

}

void dfs2(int x,int f){

    for(int i=first[x];i;i=next[i]){

        if(v[i]==f)

            continue;

        fa[v[i]]=w[i];

        dfs2(v[i],x);

        dis[x]=max(dis[v[i]]+w[i],dis[x]);

    }

    if(dis[x]+fa[x]>st){

        ans++;

        dis[x]=;

        }

}

int main(){

    n=qread();

    int m=;

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

        int mid;

        mid=qread();

        for(int j=;j<=mid;j++){

            int vx,wx;

            vx=qread();

            wx=qread();

            addedge(i,vx,wx);

            m=max(m,wx);

        }

    }

    st=qread();

    if(m>=st){

        printf("No solution.\n");

        return ;

    }

    dfs2(,);

    qwrite(ans);

    return ;

}