#include<iostream>
#include<algorithm>
#include<cstdio>
#define int long long

using namespace std;

int n,m,s;
int w[200500],v[200500];
int l[200500],r[200500];

int sum_n[200500],sum_v[200500];

long long ans = 0;

void init()
{
    scanf("%lld%lld%lld",&n,&m,&s);
    for(int i = 1;i <= n; i++)
        scanf("%lld%lld",&w[i],&v[i]);
    for(int i = 1;i <= m; i++)
        scanf("%lld%lld",&l[i],&r[i]);
    
    return ;
}

long long check(int W)
{
    long long ans = 0;
    for(int i = 1;i <= n; i++)
    {
        if( W > w[i] )// 要用前缀和，不然会炸掉！！！
        {
            sum_n[i] = sum_n[i-1];
            sum_v[i] = sum_v[i-1]; 
        }
        else
        {
            sum_n[i] = sum_n[i-1] + 1;
            sum_v[i] = sum_v[i-1] + v[i]; 
        }
    }

    for(int i = 1;i <= m; i++)
    {
        long long a,b;
        a = sum_v[r[i]] - sum_v[l[i]-1];
        b = sum_n[r[i]] - sum_n[l[i]-1];
        ans += a*b;
    }

    return ans;
}

long long _abs(long long a)
{
    if( a > 0 )
        return a;
    return -a;
}

signed main()
{
    init();

    int left = 0,right = 1000000,mid;

    while( left <= right )
    {
        mid  = (left + right)>>1;
        if( check(mid) > s )
            left = mid + 1;
        else    
            right = mid - 1;
    }
    ans = _abs(check(left) - s);
    
    if( _abs(check(right) - s) < ans )
        ans = _abs(check(right) - s);
    
    printf("%lld",ans);
    return 0;
}