#include <bits/stdc++.h>
using namespace std;
 
int main() {
  double a, b, c;
  int A, B; 
  string C;
  B = c;
  cin >> a >> b >> c;

  for (int i = a; i <= b; i++) {
   B /= i;
   B *= 10;
   C = B;
   if (C.at(C.size() + 1) ==  0) {
    A++;
   }
   B = c
  }

  cout << A << endl;

}
