T02D04Q1

#include <math.h>
#include <stdio.h>

int remain(int a, int div) {
  while (a >= div) {
    a -= div;
  }
  return a;
}

int divide(int num, int div) {
    int count = 0;
    while num > 0 {
        num -= div;
        count += 1;
    }
    return count;
}

int simple(int num) {
  int flag = 1;
  for (int div = 2; div < (int)sqrt(num) + 1; ++div) {
    flag = remain(num, div) == 0 ? 0 : flag;
    flag = remain(num, divide(num, div)) == 0 ? 0 : flag;
  }
  return flag;
}

int max_simp_div(int num) {
  num *= num < 0 ? -1 : 1;

  int result = 0;
  if (simple(num) == 0) {
    for (int i = 2; i < (int)sqrt(num) + 1; ++i) {
      if (remain(num, i) == 0) {
        result = i > result && simple(i) == 1 ? i : result;
        result = divide(num, i) > result && simple(divide(num, i)) == 1 ? divide(num, i) : result;
      }
    }
  } else {
    result = num;
  }
  return result;
}

int main() {
  char c;
  double a;

  if (scanf("%lf%c", &a, &c) == 2 && (int)a == a && c == '\n') {
    printf("%d", max_simp_div((int)a));
  } else {
    printf("n/a");
  }
}