#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
#include<vector>
#include<queue>
using namespace std;
#define LL long long
const int maxn = 1e5+7;
const int mod = 1e9+7;
vector<int>e[maxn];
int a[maxn],b[maxn],d[maxn];
int ans[maxn];
int main(){
    int n,m;
    while(cin >> n >> m){
        for(int i=1;i<=n;i++){
            e[i].clear();
        }
        memset(d,0,sizeof(d));
        memset(ans,0,sizeof(ans));
        for(int i=1;i<=n;i++){
            cin >> a[i] >> b[i];
        }
        for(int i=1;i<=m;i++){
            int u,v;
            cin >> u >> v;
            e[v].push_back(u);
            d[u]++;//终点为u的路径的条数
        }
        queue<int> q;
        for(int i=1;i<=n;i++){
            if(d[i] == 0){//把终点为i的路径数为0的点加入队列
                q.push(i);
            }
        }
        while(!q.empty()){
            int v = q.front();
            q.pop();
            for(int i=0;i<e[v].size();i++){
                int u = e[v][i];
                ans[u] = (ans[u] + (ans[v] + b[v])%mod)%mod;
                //之所以是加b[v]，是因为乘是相当于整体而言，一条就是1*b[v]相当于加b[v]
                d[u]--;
                if(d[u] == 0){
                    q.push(u);
                }
            }
        }
        LL res = 0;
        for(int i=1;i<=n;i++){
            res = (res + 1LL*ans[i]*a[i]%mod)%mod;
        }
        cout << res << endl;
    }
    return 0;
}