#include <bits/stdc++.h>

using namespace std;

#define maxn 200005

#define ll long long

#define INF 0x7fffffff

ll n,m,sum[maxn],wi[maxn],vi[maxn],s;

ll li[maxn],ri[maxn],sumn[maxn],flag;

inline void in(ll &now)

{

    char Cget=getchar();now=;

    while(Cget>''||Cget<'')Cget=getchar();

    while(Cget>=''&&Cget<='')

    {

        now=now*+Cget-'';

        Cget=getchar();

    }

}

int solve(ll val)

{

    sum[]=,sumn[]=;

    for(ll i=;i<=n;i++)

    {

        sum[i]=sum[i-],sumn[i]=sumn[i-];

        if(wi[i]>=val) sum[i]+=vi[i],sumn[i]++;

    }

    ll res=;

    for(ll i=;i<=m;i++) res+=(sumn[ri[i]]-sumn[li[i]-])*(sum[ri[i]]-sum[li[i]-]);

    if(res>=s)

    {

        flag=res-s;

        return false;

    }

    else

    {

        flag=s-res;

        return true;

    }

}

int main()

{

    in(n),in(m),in(s);

    for(ll i=;i<=n;i++) in(wi[i]),in(vi[i]);

    for(ll i=;i<=m;i++) in(li[i]),in(ri[i]);

    ll l=,r=,ans,mid;

    while(l<=r)

    {

        mid=l+r>>;

        if(solve(mid)) ans=mid,r=mid-;

        else l=mid+;

    }

    solve(ans);ll ansl=flag;

    solve(ans-);ll ansr=flag;

    printf("%lld",min(ansl,ansr));

    return ;

}