#include <cstdio>
#include <algorithm>
#include <cfloat>
using namespace std;

int main() {
  double h, m = DBL_MAX, M = 0.0;
  while (scanf("%lf", &h)==1) {
    m = min(m, h);
    M = max(M, h);
  }
  printf("%lf\n", M-m);
  return 0;
}