#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    long long int sum=0;
    int t;
    cin>>t;
    int a,b;
    cin>>a>>b;
    while(t--)
    {
        cin>>a>>b>>a>>b;
        sum+=b;
    }
    cout<<sum<<endl;
    return 0;
    
}