#include <algorithm>
#include <array>
#include <bitset>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <queue>

using namespace std;

struct BoolName : numpunct<char> {
  string t, f;
  BoolName (string t = "Yes", string f = "No") : t(t), f(f) {}
  string do_truename() const {return t;}
  string do_falsename() const {return f;}
};

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15) << boolalpha;
    cout.imbue(locale(cout.getloc(), new BoolName));
  }
} initializer;

template<typename T> istream& operator>>(istream &s, vector<T> &v) {
  for (T &t : v) s >> t;
  return s;
}

template<typename T> ostream& operator<<(ostream &s, const vector<T> &v) {
  for (const T &t : v) s << t << endl;
  return s;
}

template<typename T> bool chmin(T& a, T b) {return a > b ? a = b, true : false;}

template<typename T> bool chmax(T& a, T b) {return a < b ? a = b, true : false;}

template<typename T> int least_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_ffs(n) - 1;
  if (sizeof(T) == 8) return __builtin_ffsll(n) - 1;
}

// n must be greater than 0.
template<typename T> int least_bit_fast(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_ctz(n);
  if (sizeof(T) == 8) return __builtin_ctzll(n);
}

template<typename T> int most_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return n ? 31 - __builtin_clz(n) : -1;
  if (sizeof(T) == 8) return n ? 63 - __builtin_clzll(n) : -1;
}

template<typename T> int count_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_popcount(n);
  if (sizeof(T) == 8) return __builtin_popcountll(n);
}

class BitIterator : public iterator<input_iterator_tag, int> {
public:

  class Iterator : public iterator<input_iterator_tag, int> {
  private:
    int val, bit;

  public:
    Iterator(int val, int bit) : val(val), bit(bit) {}

    Iterator operator*() {return *this;}

    bool operator!=(const Iterator& itr) const {return val != itr.val;}

    void operator++() {val = least_bit(bit & -(1 << (val + 1)));}

    operator int() {return val;}
  };
  
  Iterator i, n;
  int bit;

  BitIterator(int n) : i(least_bit(n), n), n(-1, n), bit(n) {}

  bool operator!=(const BitIterator& itr) const {return i != itr.i;}

  void operator++() {*this = BitIterator(bit + 1);}

  operator int() const {return bit;}

  bool in(int i) const {return bit & (1 << i);}

  Iterator& begin() {return i;}

  Iterator& end() {return n;}
};

class PowerSet {
private:
  class Iterator : public iterator<input_iterator_tag, int> {
  private:
    BitIterator val;

  public:
    Iterator(int val) : val(val) {}

    Iterator operator*() {
      return *this;
    }

    bool operator!=(Iterator& itr) {
      return val != itr.val;
    }

    void operator++() {
      ++val;
    }

    operator int() const {
      return val;
    }

    bool in(int i) const {
      return val.in(i);
    }

    BitIterator::Iterator& begin() {
      return val.begin();
    }

    BitIterator::Iterator& end() {
      return val.end();
    }
  };

  Iterator i, n;

public:
  PowerSet(int n) : i(0), n(1 << n) {}

  Iterator& begin() {
    return i;
  }

  Iterator& end() {
    return n;
  }
};

template<typename T = double> constexpr T pi() {return acos(T(-1));}

template<typename T> T gcd(T t) {return t;}

template<typename T, typename... S> T gcd(T a, S... s) {
  auto b = gcd(s...);
  if (a == 0 || b == 0) return max(a, b);
  int fa = least_bit_fast(a);
  int fb = least_bit_fast(b);
  a >>= fa;
  b >>= fb;
  while (a != b) {
    auto& c = a > b ? a : b;
    c = abs(a - b);
    c >>= least_bit_fast(c);
  }
  return a << min(fa, fb);
}

template<typename T> T gcd(const vector<T>& v) {
  T g = v[0];
  for (int i = 1; i < int(v.size()); ++i) g = gcd(g, v[i]);
  return g;
}

template<typename T> T lcm(T t) {return t;}

template<typename T, typename... S> T lcm(T t, S... s) {
  T l = lcm(s...);
  return t / gcd(t, l) * l;
}

template<typename T> T lcm(const vector<T>& v) {
  T l = v[0];
  for (int i = 1; i < int(v.size()); ++i) l = lcm(l, v[i]);
  return l;
}

template<typename T> T floor(T a, T b) {
  auto d = div(a, b);
  return d.quot - (d.rem && (a < 0) != (b < 0) ? 1 : 0);
}

template<typename T> T ceil(T a, T b) {
  auto d = div(a, b);
  return d.quot + (d.rem && (a > 0) == (b > 0) ? 1 : 0);
}

template<typename T> T round(T a, T b) {return floor(a + b / 2, b);}

template<typename T> T mod(T a, T b) {
  T c = a % b;
  return c < 0 ? c + abs(b) : c;
}

template<typename T> T factorial(T n) {return n <= 1 ? 1 : factorial(n - 1) * n;}

template<typename T> T square(T n) {return n * n;}

template<typename T> T cube(T n) {return n * n * n;}

template<typename T> T norm(T x1, T y1, T x2, T y2) {return square(x1 - x2) + square(y1 - y2);}

template<typename T> bool isSquare(T n) {return square(T(sqrt(n))) == n;}

template<typename T> T clamp(T v, T l, T u) {return v < l ? l : v > u ? u : v;}

int main() {
  int d, g, r = numeric_limits<int>::max();
  cin >> d >> g;
  vector<int> p(d), c(d);
  for (int i = 0; i < d; ++i) cin >> p[i] >> c[i];
  for (auto bit : PowerSet(d)) {
    int a = 0, k = 0;
    for (int i : bit) {
      a += p[i];
      k += 100 * (i + 1) * p[i] + c[i];
    }
    if (g <= k) {
      chmin(r, a);
      continue;
    }
    for (int i = d - 1; k < g; --i) {
      if (bit.in(i)) continue;
      int b = ceil(g - k, 100 * (i + 1));
      if (b > p[i]) break;
      chmin(r, a + b);
      break;
    }
  }
  cout << r << endl;
}



Measured memory_bytes: 256