Submission

Score: 100

User: posnfor2

Problemset: อนุกรม

Language: cpp

Time: 0.003 second

Submitted On: 2025-10-10 16:18:50

#include <iostream>

using namespace std;

int main()
{
   int n;
   cin >> n;
   if(n <= 0 || n > 90) return 0;
   if(n == 1 ||  n == 2){
        cout  << 1;
        return 0;
   }
   long long a = 1, b = 1, c;
   for(int i = 3 ; i <= n; i++){
        c = a + b;
        a = b;
        b = c;
   }
   cout << b;
   return 0;
}