#include <bits/stdc++.h>

#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()

using namespace std;

int f(int a, int n) {
  return (a * 100.0) / n + 0.5 + 1e-9;
}

int solve() {
  int A, B;
  cin >> A >> B;
  for (int n = 1;; ++n) {
    REP(a,n+1) {
      int b = n - a;
      if (f(a, n) == A && f(b, n) == B) return n;
    }
  }
  return -1;
}

int main() {
  cout << solve() << endl;
  return 0;
}