#include <bits/stdc++.h>
using namespace std;
int main() {
  int p, y, s, cnt = 0;
  cin >> p >> s >> y;
  while (1) {
    int i = (s / 50) % 475;
    for (int j = 0; j < 25; j++) {
      i = (i * 96 + 42) % 475;
      if ((i + 26) == p) {
        cout << cnt << endl;
        return 0;
      }
    }
    int t = s, c = 0;
    t -= 50;
    while (t >= y) {
      int j = (t / 50) % 475;
      for (int k = 0; k < 25; k++) {
        j = (j * 96 + 42) % 475;
        if ((j + 26) == p) {
          cout << cnt << endl;
          return 0;
        }
      }
      c++;
      t -= 50;
    }
    s += 100;
    cnt++;
  }
  return 0;
}
