#include <cstdio>
#include <string>
#include <memory>
using namespace std;

class BigInteger{
private:
  enum{MAXLENGTH=14900};
  int m[MAXLENGTH];
  int len;

public:
  BigInteger(int n)
  {
    memset(m,0,sizeof(m));
    len=0;
    if (n == 0) len++;
    while (n > 0)
    {
      m[len++] = n % 10;
      n = n / 10;
    }
  }

  BigInteger(void)
  {
    memset(m,0,sizeof(m));
    len=1;
  }


  void print(void)
  {
    int temp = len-1;
    while(temp>=0) printf("%d",m[temp--]);
  }

  BigInteger operator+ (const BigInteger &a)
  {
    int i,carry = 0;
    BigInteger Temp(*this);
    if (a.len > Temp.len) Temp.len = a.len;
    for(i=0;i<Temp.len;i++)
    {
      Temp.m[i] += (a.m[i] + carry);
      carry =  Temp.m[i] / 10;
      Temp.m[i] %= 10;
    }
    if (carry > 0) {Temp.m[i] = carry; Temp.len++;}
    return Temp;
  }








  int operator> (const BigInteger &a)
  {
    int i;
    if (len > a.len) return 1;
    if (len < a.len) return 0;
    for(i=len-1;(m[i] == a.m[i]) && (i>0);i--);
    if (m[i] > a.m[i]) return 1;
    return 0;
  }
int operator== (const BigInteger &a)
  {
    int i;
    if (len != a.len) return 0;
    for(i = len-1;i>=0;i--)
      if (m[i] != a.m[i]) return 0;
    return 1;
  }

};
int main()
{
    int n;

scanf("%d",&n);
BigInteger r1;int i;
    BigInteger previous = -1;
    BigInteger result = 1;
    for (i = 0; i<n; i++)
    {
    BigInteger const sum = result + previous;
    previous = result;
    result = sum;
    if(i==n-3){
    r1=result;
    }
    }
    (r1+result).print();
return 0;
}


Edited by author 25.09.2008 01:10

Use long ariphmetics on base 10^9 or 10^18, but not 10^1 :)