C++ :

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<climits>
#include<cmath>
#define rep(i,n) for(int i=1;i<=n;i++)
using namespace std;
const int N=200010;
typedef long long ll;
int v[N],w[N],l[N],r[N],n,m;
ll ans,sum[N],tim[N],s;
int L,R,M;

ll ok(int M) {
	ll res=0;
	memset(sum,0,sizeof(sum));
	memset(tim,0,sizeof(sum));
	rep(i,n)if(w[i]>=M)sum[i]=v[i],tim[i]=1;
	rep(i,n)sum[i]+=sum[i-1],tim[i]+=tim[i-1];
	rep(i,m)res+=(sum[r[i]]-sum[l[i]-1])*(tim[r[i]]-tim[l[i]-1]);
	return res;
}

int main() {
	
	scanf("%d%d%lld",&n,&m,&s);
	rep(i,n)scanf("%d%d",&w[i],&v[i]),R=max(R,w[i]+1);
	rep(i,m)scanf("%d%d",&l[i],&r[i]);
	
	ans=LLONG_MAX;
	while(L<R) {
		int M=(L+R)>>1;
		ll res=ok(M);
		if(res<=s)R=M;
		else L=M+1;
		ans=min(ans,abs(res-s));
	}
	
	printf("%lld\n",ans);
	
	return 0;
}

Pascal :

var
  s,y,tmp,ans:int64;
  mid,left,right,i,n,m,max,min:longint;
  c,a,w,v,l,r:array[0..200001]of longint;
procedure work(t:longint);
var i:longint;
    count,tot:int64;
begin
  fillchar(a,sizeof(a),0);
  fillchar(c,sizeof(c),0);
  for i:=1 to n do
    begin
      if w[i]>=t then
        begin
          a[i]:=a[i-1]+v[i];
          c[i]:=c[i-1]+1;
        end
      else
        begin
          a[i]:=a[i-1];
          c[i]:=c[i-1];
        end;
    end;
  y:=0;
  for i:=1 to m do
    begin
      count:=c[r[i]]-c[l[i]-1];
      tot:=a[r[i]]-a[l[i]-1];
      y:=y+count*tot;
    end;
end;
begin
  read(n,m,s);
  max:=0;
  min:=maxlongint-1;
  for i:=1 to n do
    begin
      read(w[i],v[i]);
      if w[i]>max then max:=w[i];
      if w[i]<min then min:=w[i];
    end;
  for i:=1 to m do
    begin
      read(l[i],r[i]);
    end;
  left:=min-1;right:=max+1;
  ans:=maxlongint*100000;
  while left<right do
    begin
      mid:=(left+right) div 2;
      work(mid);
      tmp:=s-y;
      if abs(tmp)<ans then ans:=abs(tmp);
      if ans=0 then break;
      if s>y then right:=mid
        else left:=mid+1;
    end;
  writeln(ans);
end.