#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, r, x, s = 0;
  cin >> n >> r >> x;
  int a[r + 1];
  for (int i = 1; i <= r; i++) {
    a[i] = 10000000;
  }
  while (n--) {
    int l, m;
    cin >> l >> m;
    a[l] = min(a[l], m);
  }
  for (int i = 1; i <= r; i++) {
    s += a[i];
  }
  cout << min(s, x);
  return 0;
}
