#include <bits/stdc++.h>
const int N = 1e6 + 3;
const long long INF = 1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 7;
using namespace std;
int main() {
  int n;
  cin >> n;
  double m;
  cin >> m;
  double a[n];
  double b[n];
  double mini = inf;
  double mn = inf;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    b[i] /= 100;
    a[i] += b[i];
    if (a[i] > m) {
      continue;
    } else {
      mn = 1;
      if (b[i] > 0) {
        mini = min(mini, b[i]);
      }
    }
  }
  if (mn == 1) {
    if (mini == 1e9 + 100) {
      cout << 0;
      return 0;
    }
  } else {
    cout << -1;
    return 0;
  }
  cout << (1 - mini) * 100;
}
