import java.util.Scanner;
public class Main{
    static int N = 200010;
    static int prew[] = new int[N];
    static int prev[] = new int[N];
    static int pren[] = new int[N];
    static int w[] = new  int[N];
    static int v[] = new int[N];
    static int l[] = new  int[N];
    static int r[] = new int[N];
    static int n,m,s,sum;
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();
        s = sc.nextInt();
        int min = Integer.MAX_VALUE,max = -1;
        for(int i = 1;i <= n;i++){
            w[i] = sc.nextInt();
            v[i] = sc.nextInt();
            min = Math.min(min,w[i]);
            max = Math.max(max,w[i]);
        }
        for(int i = 1;i <= m;i++){
            l[i] = sc.nextInt();
            r[i] = sc.nextInt();
        }
        int res = Integer.MAX_VALUE;
        int left = min - 1,right = max + 2;
        while(left+1 != right){
            int mid = (left + right) / 2;
            if(check(mid)) left = mid;
            else right = mid;
            if(sum < res) res = sum;
        }
        System.out.println(res);
    }
    public static boolean check(int x){
        int Y = 0;
        int sum = 0;
        for(int i = 1;i <= n;i++){
            if(w[i] >= x){
                pren[i] = pren[i - 1] + 1;
                prev[i] = prev[i - 1] + v[i];
            }
            else{
                pren[i] = pren[i - 1];
                prev[i] = prev[i - 1];
            }
        }
        for(int i = 1;i <= m;i++){
            Y += (pren[r[i]] - pren[l[i] - 1]) * (prev[r[i]] - prev[l[i] - 1]);
        }
        sum = Math.abs(Y - s);
        if(Y > s) return true;
        else return false;
    }
}